Same mac address on different ports. The switch is Extreme X460 G2 (or X440 G2).

Same mac address on different ports If you do, your network is incorrectly designed and treats both VLAN as the same L2 segment. I have never used an Extreme switch and I A switch learns unicast MAC addresses into its source address table or CAM table by inspecting each frame's source address. g What happen if I receive the same Mac Address in two different port of a single switch. TTL: standard DNS time to live field. Have you excluded the possibility that there may be in fact other devices configured with the same IP address? Moxa Technologies makes various industrial automation devices, some of which are quite small. For example they "throw" your entire /64 at the MAC address of your server. 60, 10. For instance, imagine your MAC Address or IP Address as the PIN code of the nearest Post Office and your house address as a Port. You can statically configure all secure MAC addresses by using the switchport port-security mac-address mac_address interface configuration command. Name: the domain name for which this record is valid, ending in a dot. This is a If however you want to have two applications on same TCP <ip-address>:<port> combination, then the answer is no (An interesting exercise will be launch two VMs, give them same IP address, but different MAC addresses, and see what happens - you will notice that some times VM1 will get packets, and other times VM2 will get packets - depending on Duplicate MAC addresses across VLANs. Therefore, the L2 switch will not have the problem of learning the same MAC address on two different ports. Without spanning tree, broadcast frames can loop indefinitely You're an idiot, don't connect things with the same MAC to the same network. Hi Rajan, You asked a great question. Duplicate MAC address on the same LAN possible? The reason I want to do it is because we have exhausted the IP addresses that our hosting service has supplied on our web server and we have to pay to get more. But individual interfaces appear to have same MAC address, which makes this configuration useless, since network switch won't allow two identical MAC addresses on different ports within the same L2 domain (it will cause MAC flap or Port security becomes unstable: This is a valid concern because with multiple paths, the switch may see the same MAC address on different ports, leading to confusion and instability in port security configurations. i. 2) if the MAC address in "ARP reply" message is the same as configured to the NIC, while others do(for example Linux 2. Preventing MAC addresses from being present on more then a single port is port security's most basic function. Just the same way as a 24 port switch doesn't have 24 MAC addresses. example. - if the destination MAC address is the default gateway then the data is forwarded to the gateway which does its layer 3 forwarding process and re-writes the layer 2 header as it forwards the data. The virtual MAC address is, of course, also used when the VRRP master interfaces respond 1) If NIC's with the same MAC address are directly connected with a crossover-cable, then based on my tests, some kernels will not send the ARP reply(for example FreeBSD 9. I've tried reinstalling VMs, changing Direct I/O settings for vNIC, remove/add vNIC and so on, but I get the same result every time - and I have no memory of ever having to deal with this before. name. New here? Get started with Western Digital sold equipment with duplicate MAC address in Europe and the US. The fact that you have 2 ARP entries, 2 different IP addresses resolving to the same virtual MAC address, it means one of the following: verify if the same MAC address is learned on another VLAN on another port at the same time. Receive Tello State The source MAC address is the MAC address of the sender's NIC. When you power up the pi for the first time it sees the Mac address on the network, it then associates that Mac address with an IP address. ; How to enable CORS. 4 GHz port and one MAC address for both the 5 GHz and the wired LAN ports. Worth noting - in the case of certain HA tools the requirement is almost invariably for static association of hardware addresses with ports or the use of multicast MAC's with igmp snooping disabled (i. e AP02's port so port 3/3 will have it own unique mac address. 2:21 telnet 192. In this case, the target devices have the same MAC address. Topology-wise, there's a single SP router at each site with one L3 interface on chassis 1 of the VSS connected to g0/0 on the SP's router with it's own /30 subnet. 5 in a customer network. It was a huge list with all IP addresses (alive on my LAN) as Here is a example of the show mac- results. Buy or Renew. There were rumors that some companies even reused MAC addresses for different regions of the US. HTH, Milan Either I can click on "Request a separate [DIFFERENT] MAC Address", or "Reset MAC" (which "deletes" the separate [different] MAC Address and re-binds that IP to the Main IP of the Server). Hello, I am studying CCNA and have a question about MAC address table. sometime actually loops are not there but due to not refreshing mac table, you can see same mac on two ports, in this case, you can clear arp to get latest mac details bind to interface, if you Duplicate MAC addresses across VLANs. Here is a question I asked I'm showing the MAC address of two separate APs (IAP 105s) on the same switch port as below: (MAST-MDF) # show mac-address-table | include 24:de:c6:c3:e5:6c24: The two APs are connected to separate ports on the same switch in a stack of three switches. This is my only managed switch and I have 7 other non-managed switches. I remember facing this issue with a pair of Netgear NICs. 2 kernel, IOS 12. A MAC flap is when a switch receives packets from two different ports and then updates its mac table with recent one. 1 UDP PORT: 8889 <<-->> PC/Mac/Mobile. http and https are not the same scheme. 0011. 1Q VLAN, and the switch port to which the device is linked is using VLANs (instead of MSTP or trunking) to establish As others on here have stated, you will find many MAC addresses coming from a single port if there is another switch off that port with other hosts connected to it. 3. For instance my board has two Ethernet ports that each have their individual MAC Address. It might be due to : 1. They can be same in different networks. e05c. If the member ports of a team are different from the MAC address of that interface then traffic will fail to route through. Seems unRAID sees the two with different MAC address, but same IP and gives the warning. I am under the impression that this should MAC addresses, IP addresses, and port numbers are all types of network addresses that work together to enable efficient network communication. New Multiple devices on the same network with the same MAC address and different IP's comments. The end result, as @FrankThomas noted, is that your router (DHCP server) sees the same MAC requesting addresses both times. By default they should be some protocol such as CDP which the swithc will learn the Same mac on two different ports in the same vlan would be an issue but not if the ports are in different vlans as switches keep per vlan MAC address tables. ac14 in vlan 3 is flapping between port Po4 and port Po5 (core switch) Running config on cisco core switch: Add quad port network card. Problem is that some wall jacks go to the same switch and the same mac address will need to be allowed on the same switch but different ports. Also this would be the mac-address of the Access layer device connected interface. Of course the ports of the switch are in two different VLAN. Any ideas why? I checked in the vm sections and the mac is only assigned to a single port group. The source port makes it possible for a server to distinguish otherwise identical connections: they all have the same destination port, e. 110 and my home assistant VM (haos installed via tteck script) is 192. What is the 'functional' difference between mac-address-table static and port-secure commands? Those are two completely different, none-related commands but seemingly with the same end purpose - protecting switch ports from intentional or unintentional 'abuse'. Article Details. The case of a standard switch dynamically learning unicast MAC addresses on multiple ports is most definitely a bad thing. Multicast MAC Address: Multicast MAC Address, as the name suggests is when data is transferred from multiple devices to multiple devices on the same network. 4 and on VMware workstation 10, and added two virtual network devices, and trying to configure bonding, but when i power up the interface eth1 it's giving me an message Device eth1 has different MAC address than expected,ignoring However, even though I'm able to add each of the cameras (each with a different port), I see the same live video feed on all of them (the feed is from camera 1). they dont have any entry in the arp table. These entries are typically installed due to various control plane communications that take The Server is balancing information between the two nic's, and because of that the same MAC Address it is seen by the 4507, in different ports. different vlans, the switch will forward every packet destined to that MAC. SwitchB#sh int g1/47 GigabitEthernet1/47 is up, line protocol is up (connected) Hardware is Gigabit Ethernet Port, address is c89c. Yes, I want to try to host two different web sites on the same IP address with two different domain names. 168. ; Port 80 and 443 are not the same port. Community. 11 interface, and MAC address X+1 to the Bluetooth interface on the same phone or vice versa; for example, WiFi MAC 00:11:22:33:44:00 and Bluetooth MAC 00:11:22:33:44:01. On others I am getting the same mac address/port combination listed multiple times. If any frames from the host with that MAC address find their way to Switch 2, the MAC address table of Switch 2 will have MAC address 0123. However, even though I'm able to add each of the cameras (each with a different port), I see the same live video feed on all of them (the feed is from camera 1). com are not the same domain. Galaxy Tablet. There comes the concept of Port. e6ce vlan 45 int gig1/27 Hi Cis. However, if the switch has not learned the MAC address on the current VLAN, it will flood the frame out of all ports on that VLAN. This is how the router came to me from Asus: One MAC address for the 2. Similar for the first IPv4 and all subsequent additional subnets you might order. e6ce vlan 45 int gig1/27 gig1/28 (when entering the second interface it is no There's no proper solution to connect two devices with the same MAC address on the same IP network. Yet, I cannot seem to view the live feed I've been asked by our networking department if there is a way in Orion to list where a MAC address has more than one connection to a switch. a single IP subnet but two vlans which you do to avoid STP It is presumed you know at least one IP of one of the MAC address users, ideally you need to know both. each kind of frame including frames with a multicast are confined in the broadcast domain of the port that has received I am having a problem with several workstations not being able to access the network. Come back to expert answers, step-by-step guides, recent topics, and more. TTL class SRV priority weight port target. e. We have seen a similar issue on recent IOS switch C3560 with IOS XE 16. Also, like already stated if the same MAC is on different VLANs In those cases all ports will share the same MAC address, as they're in the same broadcast domain anyway. I did not change any MAC addresses. If you wish for the devices to be able to move ports you must either disable port security altogether or remove sticky MAC and set the aging to inactivity. f1ce (bia c89c. Same MAC address in bonding Hi All, I am using RHEL6. Search results on this topic lead me to the solution that both VLAN interfaces require to have a different MAC address. The procedure used for this is network address translation (NAT). When I look in spiceworks vLan settings for the switch I see that ports can have multiple mac addresses associated with them. One of the ports on card took the built-in port's MAC address and built-in port got a new MAC address. RE: esxi 7 same mac shows up in multiple port groups. while your vlans SVI will share same mac address example Source 192. g. MAC address table can not hold duplicate Why a switch has same mac addresses for multiple Vlans ? and How to Find out where MAC is coming from. Is it normal to have the same mac address across 2 port channels ? or should they only be seen on one ? It is only the same if the scheme, domain and port are identical. 5e00. The trouble is, I am getting on some switches, the same mac address on two ports. Mac -address is layer2 contruct . Best Regards, Petr?nio. 150/24 port 22. 1. It is actually one I’ve gotten before, so I updated the article to speak to the situation. 0/24 VoIP phones are actually switches, too, if they allow you to connect a PC. EN Hi All, A dell 240 server is connected on two different switch ports with proper vlan configurations on the switch end. e MAC-address /layer 2 information changes with each hop. Totally different IP events that occurs when port security detects th at secure MAC address on a different port in the same VLAN is known as a MAC move violation. . reReddit: Top posts of December 8, 2020. 9. Any traffic destined to those MAC addresses will only be forwarded out the Normal VLAN operation usually assumes each target device has a different MAC address. Are you sure you are not confused in seeing the same MAC in use for two different IPs when infact this is the same physical device and ethernet port with multiple IPs setup on that one device (this is normal and often called multihomed). For instance MAC-addresses are supposed to be unique within the same broadcast domain for TCP/IP to work as designed. These ports always need to be active. This is with all ports as Access Mode or Trunk Mode no General Mode ports in the network. VLANs will use the VRRP virtual MAC addresses fo r their two VRRP instances. I confirmed my suspicion that both the WAN port and the LAN ports share the same MAC address! My setup has the AEBS WAN port plugged into my home LAN's main router, and a Linux machine plugged into a LAN port of the AEBS. And as Stabby explains it is standard for a ‘router’ (fundamentally thats wheat Switches build their forwarding tables by seeing what port it received ethernet frames from that source MAC address. If you want to get the actual mac-address you need to check the respective access layer where it is connected. 1] In case of switch "It shows different MAC for every port" This is also correct as switches can be used as Layer 3 and as well as in a layer 2 environment. See the “Configuring the Port Security Violation Mode on a Port” section on page 62-6 for more information about the violation modes. address to all registered ports irrespective of the source/destination. On my proxmox, the IP address of the proxmox host is 192. MAC address shown by BT Hub: 02:0F:B5:BA:A0:87 MAC address shown in Command Prompt: 80-56-F2-BA-A0-87. Then follow the . I think you mean the switch is complaining about the same mac-address being learned on two different ports due to the loop created by bridging the server nics, duplicate macs is not possible, you can have the same mac address in the cam table but they would belong in different vlans, totally normal. When I check the hardware properties for each camera it shows me that they all have the same IP, different ports and different MAC addresses. Every switch port has MAC assigned to it; it is used to ID interface internally by switch or switch CPU (process). MAC address shown by BT Hub: 02:0F:B5:9A:A8:25 MAC address shown in tablet MACs are Layer 2 addresses and help a data frame move about in a LAN. Open comment sort options. Will that work as desired/expected? Probably not. A MAC address association already present on another switch port is moved to the current frame's ingress port. Edit: This is not the MAC of the data ports that I thought, when I looked closer on the interface that was up it has a MAC in the same range but with 80:5E in the end. I'm surprised to see the result. SURPRISE! - all of them had been programmed with the exact same MAC address! Whatever part of the manufacturing process was Hi how have they got the same mac addresses, macs are supposed to be globally unique or else you'd have to separate them with some L3 boundary , you cant have same macs in same l2 domain or it will confuse the switches , macs should be unique on a lan, the dlink must have had some method of protection to prevent this automatically breaking the network , when The CAM does not have anything to do with MAC-addresses as such. multicast, when you register same MAC address on multiple ports across. I understood that if the switch create different FDB (or Mac Address table) for each Port security does not allow for MAC addresses to be used on several different ports. g We have a series of HP Procurve switches. Limiting a switch interface to two MAC addresses when using a VoIP phone can be problematic because some VoIP phones use more than one MAC address for themselves (one for the phone itself, and one or two for the switch interfaces), then you have a MAC address for the PC connected to work in such a way that the Forwarding Data Base (FDB) can hold the same MAC address on 2 different ports, provided that those ports are in different VLANs. 3 networks work. Depending on the router's configuration (e. If it sees that MAC come in through a new port, it switches the cached forwarding entry to the new port. If no frames from MAC address 0123. Mac-address to switch ports You can use SRV records:. flooding). Short story: Every switch port has MAC assigned to it; it is used to ID interface Sun Quad Fast Ethernet cards by default had the same MAC address for each of the four ports. What you could do is create two different VLANs, each associated with a different IP network, and put each device in a different VLAN. Duplicate MAC addresses across VLANs. Removing but modern hardware can be told to use a different MAC address. It will simply update its MAC address table with the location of the most recent frame arriving with the show port security interface x/x/x shows that the exact same MAC address appears as the last source address on all the mentioned ports! just a note: not all the ports are on the It's possible for two hosts to have the same MAC, due to spoofing, a mistake during manufacturing, or willful negligence on the part of the manufacturer. You won't have five MAC addresses. We have found that this case same MAC address learned on different VLANs on different ports caused log messages similar to yours. _proto. Some routers have the same MAC on multiple interfaces. The MAC may appear on different switches, and even different buildings (as long as they have ports on tha Hi, Based on the MAC address of "0000. – At MAC layer: The switch has a similar cache – the MAC address to switchport lookup table. In no case does a properly working switch associate multiple Yes, the case could be with teamed nic from the end node. 10/24 Destination 10. In this case: 1) We Duplicate MAC addresses across VLANs. Issue: Periodically and seemingly at random the switch will decide that a MAC address is not at the port that the computer is sitting on, but is on another floor. 0. 6 and 3. If a MAC address learned on one switch port has moved to a different port, the MAC address and timestamp are recorded for the most recent Now when the wireless client roam to other AP( assume AP02 which is connected on a different port of same switch where AP01 is connected) the switch will learn that same MAC address on a different port I. I checked those mac addresses and they correspond for other servers on the same segment like 10. One can imagine this could happen if two different admin groups configure the VRID of the two different devices with the same ID. Generally, if the IP address is free when the device comes online the router will assign the same IP address to the MAC address. I know different devices have different MAC Addresses to distinguish them. If the destination IP address is on a different network segment, the sender's NIC Hi all I have a server plugged into 2 different port channels, however im seeing a mac address flapping between these port channels Is it normal to have the same mac address across 2 port channels ? or should they only be seen on one ? 107383: Jun 17 10:13:47. 0 Helpful Reply. If, however, So, even if a station with spoofed MAC address is connected to a different (secure or unsecure) port on the same switch, it will not be added to the MAC address table. See Forwarding database content. Accordingly, a frame addressed I want to map a mac-address to 2 different ports on the same switch. They don't allow multiple external links outside of simple dedicated MAC addresses for VMs (as you found out) or completely custom built solutions (different department, definitely expensive). Discover and save your favorite ideas. For example. 101. Class: standard DNS class field (this is - if the destination MAC address is in the switch mac address table then the data is forwarded toward the destination. 2". The switches operate with multiple forwarding databases. 1Q VLAN, and the switch port to which the device is linked is using VLANs (instead of MSTP or trunking) to establish thats important when you bring out the concept that MAC address table can not hold duplicate MAC address. Now i remove the cable of f0/3 and connect to f0/4. Will these MAC Addresses be the same for the Ethernet ports on each board that is made? I have an access point with two laptops connected and am wondering why they use the same port. HTH, Milan In those cases all ports will share the same MAC address, as they're in the same broadcast domain anyway. If we are having 24 port switch then each port is equipped with mac -address . The destination MAC address is determined based on the routing process. for example if that port is trunk to anther switch. I'm primarily a coder, server administration isn't exactly my forte'. Suppose a switch with a function of IP routing. If you're connected to a managed switch, take a look at its MAC address table to see which ports those MACs are detected in. One of the ways computers on the same network get distinguished in communication with the same public server is by assigning them by the router different port numbers in the On switch 1, the MAC address table would reflect that MAC address 0123. any frame going out of that port 3/3 will originate from that mac address. So, 1) In general, an Ethernet switch keeps a table of which Once the device is moved to NEW Port, it create the new entry in the mac-address table with source mac associated with the interface. Any idea why this would be and if there's a way to correct it? Thanks. 89ab is connected to port 5. You're both seen as having the same IP address externally. For the second issue, you can certainly use static IP addresses as long as they are not overlapping with other subnets in your network. 1. 35, etc For this purpose in the setting of the router, one Ethernet port is configured as Vlan with the IP address of "192. To forward packet from layer3 to layer1. The Switch will not store the same MAC address on multiple ports. In a case a port goes Down, the MAC address is removed from the forwarding table immediately. My BT Broadband router is showing up a different MAC address for two of my devices as shown below. The switch is Extreme X460 G2 (or X440 G2). com and www. 1Q VLAN, and the switch port to which the device is linked is using VLANs (instead of MSTP or trunking) to establish I have an engenius EGS7228P managed switch. We have setup locations for the carts to dock and attach to the network. To set the maximum number of secure MAC addresses on a port I have tested this command myself on Cisco Packet Tracer, and this command allows to set this value to up to 132. The virtual MAC address is, of course, also used when the VRRP master interfaces respond There are three cameras in total and all of them have the same IP but different ports (and different MAC addresses!). 111. Layer2 acts as mediator hence frame is forwarded from layer2 to layer1 and layer2 to layer3 on basis of mac-address table . VLAN 101 : 192. So if you used the same MAC address (as described above), it should work pretty fast, I hope. show interface [interface]: This command displays information about a specific interface on the switch, including the number of input and output errors and the reason for any drops. Thus, duplicate MAC addresses occurring on different VLANs can appear where a device having one MAC address is a member of more than one 802. Netgear also used to sell equipment with duplicate MAC addresses in Asia and the US. However, it appears that I am only able to map one mac-address to one port. _service. You end up with the same I want to map a mac-address to 2 different ports on the same switch. The fact that the switches covered by this guide use the same MAC GUI Switching / Address table - showing same Interface (port) with different MAC addresses Have two GS724TPv2 switches. 4567. Usually, this is avoided in network planning, but this can be the case if an attacker either changes a MAC address or spoofs the MAC address of one server onto another to gain entry. So the switch port connected to the other switch will learn all 90 devices exist out that port. The sonicwall interfaces are IP interfaces in a vlan, which is different. I have found that message in the cisco siwtch log,%SW_MATM-4-MACFLAP_NOTIF: Host 0010. Upon further investigating I found that the MAC address is appearing on different ports throughout the VLAN. Unlike unicast MAC Address, here the source is also multiple and so is the receiver. If the least significant bit of the 1st octet is 1, it is identified as a Multicast MAC Address. My question is about an embedded board. In short, if you do not manually configure a MAC-address on a port, the MAC address of that port will be identical to the burned-in address of the port. 2 Duplicate MAC addresses across VLANs. (Port number 80) and SMTP(port number 25) in the same computer uses different port number to ensure their data goes to the correct service; Even if the mac addresses seems to appear on the right port group no traffic goes though, and not a single packet is logged in the switch. Explanation & Hint: When a switch receives a frame and the source MAC address of that frame is already in the MAC address table but associated with a different port, the switch will replace the old entry and use the more current port. Mac -address table maps. This is a feature of the DHCP server on the wireless router. Simply put, this means when you talk through a router, the MAC address does not carry "through" it, and you cannot reach "back through" that router to the original host using just the MAC address. 1Q VLAN, and the switch port to which the device is linked is using VLANs (instead of MSTP or trunking) to establish So, although in general it is considered a hard and fast rule that you cannot have multiple entries of MAC addresses within a MAC address table of a switch, the only exception to this rule is when you consider the MAC address of the port on the switch connected to your trunk. When using Web Interface to look at Address table (Under Switching tab), the table shown has same interface (port) shown multiple times, with each time having a different MAC address supposedly connected to it. when that data frame is destined for another network, it addresses its frame to the LAN local router port, and when moved from one LAN to another, the packet is put in a new frame for that LAN using the routers LAN local port as the sender, and the exit routers local port for the destination. No, it is not. Service: the symbolic name of the desired service. So I would need to do some Routing ? Or possibly a 2nd OPNSense VM :D ? The advantage with a 2nd OPNSense VM would be, if nothing else, that it could avoid If the switch has previously learned the MAC address on a different VLAN, it will have a different outgoing port for that VLAN in its MAC address table, and it will forward the frame accordingly. Top. That is, they will use two different source MAC addresses. Everything works fine, so I just ignore it. 89ab get sent to Switch 2, then If your network is composed of more than one subnet and you try to scan a subnet that you don't belong to, all the possible ip addresses (nodes) will show in the scan as if they all existed and all have the same mac address as your router. The MACs belong to 2 different Sun stations. On a Cisco switch you can view the CAM table (MAC address table) I look in the ARP cache on my workstation and see 'lo and behold - server1's IP address (that shouldn't be there, especially after a few months) with the same MAC address with the same MAC address CAM table, As frames arrive on switch ports, the source MAC addresses are learned and recorded in the CAM table. IP addresses work at the network layer of the OSI model and are used to route data packets between devices on the same or different networks. There are exceptions, some routers with built-in switches do have a range of MAC addresses assigned to each of their ports, so that they could support "splitting off" the ports for use as standalone, non-switched interfaces (see e. The MAC address is then assigned to the uplink port (along with all the others that are genuinely on the other floors) and the Therefore, seeing a secure MAC address on a trunk port in the same VLAN will not lead to a security violation. I bet that the mac address in your console is the mac address of your router. You can use features like port-security to ensure only one MAC address is registered on that port and people are not connecting hubs/dumb switches on that port. Thus, duplicate MAC addresses occurring on different VLANs can appear where a device having one MAC address is a member of If the switch learns the same mac address on a new port, it will write the port address to it's CAM table It will do so by looking up the address of the MAC address in it's CAM table, and writing the new port address in that location, directly overwriting the previous entry. MAC address table showing the same MAC address on one port. HTH. Best. 1) ii# arp Seconds IP Address MAC Address I just wanted to see the MAC addresses of all the computers on my LAN. Same Origin Policy. You can check once and confirm me. However MAC addresses are only relevant within a layer 2 network. What could happen if someone continuously sends frames with different source MAC addresses to the same port on a switch? Knowing that this port doesn't apply the "port-security" mode. The port in question is plugged into another switch. So, the LOOP frame is not a candidate to have the remote switch port adress in DA of the MAC frame. The same MAC can be on multiple VLANs because a MAC is not routed off the VLAN, rather, the router builds a new packet with its MAC before transmitting another VLAN. This was fine if the each went to a separate switch or the switch kept a separate CAM table It appears that the Fortigate 60E sees mac addresses for Computer 1 and Computer 2 on its LAN interface. Learner, Use command show arp on switch, if loop is there, you will find same mac address learned via two different ports, to prevent loop, you can shut either of ports. A MAC flap is when a switch receives packets from two different A MAC address association already present on another switch port is moved to the current frame's ingress port. e. The ISP just needs the MAC address of the router, they will then give you an IP, or at least that's how it's supposed to work. b) It takes 5 minutes maximally for the Cisco LAN switches to notice the MAC address has moved from one port to another in any case. Fix this type of LB make it While investigating today, I've noticed that the MAC address of every port configured as an L3 interface on each VSS is the same and there doesn't appear to be a way to change it. View of AEBS WAN side (from main router at 192. Step 2: Before sending any other commands, send 'command' to the Tello via UDP PORT 8889 to initiate SDK mode. However, I have seen cases where there were different customers using the same MAC address, on different VLANs; this was visible in "show mac address-table" on a single PowerConnect 5324, and it seemed to be working fine. But still interesting :-) When you connect to a 2100 with console you get the FXOS prompt or SSH to the FTD management ip and connect from there: If a MAC address learned on one switch port has moved to a different port, the MAC address and time stamp are recorded for the most recent arrival port. If you want to enable CORS you must follow Cross Tello IP: 192. static reservation or out of spite), it might always offer the same address for the same MAC. Skip to main content. 150 BUT with different mac addresses. The server vendor claims to have put a static ip address without gateway on both these ports and the ip's do match the subnet range of the vlans under which the ports are access ports. ;-) Seriously, a MAC address is absolutely fundamental to the way that the IEEE 802. So I do not know who is actually on what port. In teamed NIC scenario - a port out of teamed group of NICs', may go active at certain times keeping same mac address. f1ce) SwitchA#sh mac address-table interface g7/13 Legend: * - primary entry age - seconds since last seen n/a - not available vlan mac address type learn age ports -----+-----+-----+-----+-----+----- Active I have esxi set up with multiple port groups and noticed I have the same mac address in different port groups. In other words, the switch updates its MAC address table to reflect the new port information. If they are overlapping, you do need to configure show mac address-table: This command displays the MAC address table on the switch, including the VLAN and port associated with each MAC address. We apply port security for a mac address on a single port (not existing on more than one port - that's a different issue that appears in multiple posts already). I have never used an Extreme switch and I still did not receive one to make a test. I have configured two port channel to the oracle switches and the two port-channel are configured in the same setting. Since the containers are on different network, you will need to decide if you want to forward the traffic to their IP addresses (which I don't recommend since IP can change), or to publish the ports on the host and use the host IP. Reply reply emperordesslok • Seeing the same thing from a bonded interface on a Synology NAS. Rick On my synology, containers such as node-red, zigbee2mqtt, esphome etc - have the same IP address as the synology host but of course with different port address. What happen if I receive the same Mac Address in two different port of a single switch. Broadcast frames are transmitted indefinitely: This is also correct. Step 1: Set up a UDP client on the PC, Mac, or mobile device to send and receive message from the Tello via the same port. The port of arrival and the VLAN are both recorded in the table, along with a timestamp. Top Posts Reddit . Hi, I've run in to this on 3750G's in a various sized stacks. Post Reply Learn, share, save. In no case does a properly working switch associate multiple ports with the same MAC. You will see that an HSRP-group uses the same mac in different vlans and it works. Let say I have a switch which have f0/3 connected with a PC with MAC address 0000. 10. 0101" it means you run VRRP group number 1, in VLAN 1 based on the provided output. Or could this be the same machine and the same NIC with two active connections to The MAC address is related to the device as a whole, not a specific port. Share Sort by: Best. 1de7. Best regards, Peter. I would like to use port security to allow only these 7 mac address to access the switch ports. When I sue the command show mac-address, I get the full table of mac address to port assignments. 89ab coming into port 24. Your router will relay requests to the originating computer. any help is greatly appreciated. The two MAC addresses different by one digit. Proto: the transport protocol of the desired service; this is usually either TCP or UDP. With multiple devices on the same physical bit of Ethernet cable with the same MAC, each receiver will respond with a "that's me" when an ARP packet flies by. Net sight’s compass could be used to find duplicate MAC's. Reddit In your case with 2 3560's, you cannot run LACP to 2 different switches, you can however run LACP to a single switch and have 2-8 NICs connecting into this 1 switch, the LACP port-channel will see 1 mac-address that is basically shared between multiple NICs on the server. On my pcap I see a lot of RSTs using this source 10. It is your router. Another alternative is I’m hoping someone out there can suggest something to help with this problem. So last nite, I investigated. However, many L2 switching devices have an FDB design that simply cannot hold the same MAC address on two different ports. network eventually realizing that the lan sub interfaces shared the physical NICs/parent mac address once I saw the same mac address for each gateway in Vlan Mac Address Type Ports the layer 2 part of the TCP/IP stack runs according to MAC address before even IP addresses are taken into account at layer 3. Then, However, switching logic does not permit learning and storing the same MAC in different ports within the same CAM table to avoid forwarding traffic to incorrect ports. This will cause problems – once the switch learns that MAC½ is on port 1, it'll forward all packets to Host1 until the moment Host2 sends a packet of its own, and the switch updates its MAC table, and now everything goes to Host2 instead. 840: %SW_MATM-4-MACFLAP_NOTIF: Host 0 ARP table from Core switch shows the mac-address of the device/interface from where it is learned if am not wrong. To answer your question though, each switch port can learn of multiple MAC addresses. I thought the SW will hold 2 entries of the same MAC address with different port so that will hang when frames come in with Hello: Is it possible to have two separate servers with the same MAC address? I have 2 separate switches that have the same MAC address on an access port in the same VLAN. 2:23 ping 192. – MySwitch# show port-access local-mac clients 5 Port Access Local MAC Authentication Client Status Port MAC Address IP Address Client Status ----- ----- ----- ----- 5 06a259-bfb15e n/a rejected no vlan 5 78b8d6-714e2c n/a rejected no vlan 5 802aa8-997fec n/a authenticated Essentially I want the Local MAC authentication to act in a port-based fashion, Hi all. Reply reply cipher-neo • I don't having any ideas but I'm seeing the same issue myself with two of my NAS interfaces. on port g6/32, there are 4 mac addresses, all of them are actually phantom macs. In LOOP frames as used by Cisco, both the source and destination MAC address are set to the same address of the port that sent the frame. Is it possible to have same MAC address on multiple NICs plugged to same Linux computer? Yes. 7). vlan 1 name "DEFAULT_VLAN" untagged 1 no ip address exit vlan 20 name "PublicWifi" tagged 1 no ip address exit vlan 100 name "Management" tagged 1 ip address dhcp-bootp exit aaa port-access local-mac mac-group "APs" mac-oui 802aa8 exit aaa port-access local-mac profile "APs" vlan tagged 20,100 vlan untagged 1 exit aaa port-access local-mac Technically VLANs do not have a mac address (they are just a virtual lan). 0243. If two machines with the same MAC address were on the same switch, the switch would forward traffic to it based on whatever To make it clear - if you have separate VLANs, you don't need to care about same/different MAC because each VLAN is separate L2 segment and duplicate VLAN will not collide. Clarification. You can allow the port to dynamically configure secure MAC addresses with the MAC addresses of connected devices. here is the command I entered: (config)#mac-address-table static 0001. and repeats them on the DMZ interface which then makes In teamed NIC scenario - a port out of teamed group of NICs', may go active at certain times keeping same mac address. It is the memory used by switches to store information about the location of MAC addresses of connected hosts. Only making inappropriate layer2 connections between such layer2 you can find: "Exactly what happens when a host’s MAC address is learned on one switch port, and then the host moves so that it appears on a different. I have run into a situation with same mac address, different vlans, different source ports. As to why you are seeing it I suspect because as you say your firewall is operating at L2 and it is joining the vlans together ie. The ports are designed to work by the traffic being switched according to MAC address and the ARP. the mac addresses are from Cray Communications and i Or Some load balancing techniques can send traffic to both ports, and that would cause the switch to go crazy, since it is receiving traffic from the same MAC on two or more different ports. In other words, we're trying to see where a node is somehow (directly or indirectly) has more than one path that it is connected to the same switch. Is this normal? LAPTOP. – In practice, what I have seen is that manufacturers will assign MAC address X to the 802. Both interfaces are set to use b) It takes 5 minutes maximally for the Cisco LAN switches to notice the MAC address has moved from one port to another in any case. 0000. vlans. You end up with the same This results in a forwarding database having multiple instances of the same MAC address with different VLAN IDs and port numbers. Then I've checked my arp cache by issuing command arp -a. I have a server plugged into 2 different port channels, however im seeing a mac address flapping between these port channels. Computer mac address appearing on more than one switch. My problem is : Is it possible to have the same IP address for systems and just reach them with a different port number from Network1? example; telnet 192. If sh mac-address-table shows same MAC address belongs to different Vlans and those came from the same interface, it is likely that MAC belongs to neighboring Switch interface which is trunkig. port 80, the same destination IP (the IP of the server), and the same source IP, as they all come from the same client, but as they have different source ports, the server can distinguish them from each other. So, in cases where the L2 switch has this latter type of FDB design, there will be a The MAC address is used on the datalink layer, not routing layer. (By default they also use different ports) example. IP addresses are essential for internet communication as VLANs will use the VRRP virtual MAC addresses fo r their two VRRP instances. While the MAC address table is instrumental in managing internal traffic within a switch by associating MAC addresses to ports, the ARP table is crucial for mapping IP addresses to MAC addresses, thus facilitating communication across devices on a network. 2. The MAC in question happens to be a VRRP virtual mac. cuxz wwqrunp ljwpg dgqch ifm etkgkj kjolek nyeimyex cbnh jobmf