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I initially had issues with an Axis IP camera not staying online. I replaced with new camera. The new camera works perfectly fine. However, I cannot access it via HTTP or ping from a specific server (Server2). Here is the layout:

Camera is attached to port 6 on switch 2, Server is attached to port 17 on switch 5. These 2 switches are connected via fiber channel group on Switch 1. I have several other switches at this facility. Any switch that travels through switch 1 to get to switch 2 cannot ping the ip

running configs: Switch5 Switch1 Switch2

I can change the IP address to different ip in the same subnet and it works perfectly. This problem seems to be symptomatic of a duplicate IP address on the network, but I cannot find another device with that IP. Something is blocking/preventing access for Switch 5.

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  • You can check the arp table on the subnet gateway to get the MAC address(s) used by that IP. Then you can check the MAC address table on the switches to see which port that MAC is coming from.
    – Ron Trunk
    Commented Jun 8, 2020 at 18:47
  • Is there a permanent ARP table entry with the MAC address of the old camera placed in the server? That could be the problem if the server is trying to contact the old camera. Remember that frames are delivered via MAC address, not IP address.
    – Ron Maupin ♦
    Commented Jun 8, 2020 at 21:40
  • Thanks Ron, I cleeared the ARP table on the server. It has the correct IP/MAC in it. I have about 12 switches. All of the switches that are routed through switch 1 to get to the camera switch , cannot ping the ip. I feel like the problems lies on switch 1, but I don't know where to look. Switch1: drive.google.com/file/d/1Zr-XewW2W5mlwqSJasM19MX-WuzFQNQC/…
    – Rob Gates
    Commented Jun 9, 2020 at 12:58
  • If you remove the "correct" camera, can you still ping the IP? Did the arp table change? Check for static ARPs, as @ronmaupin suggests.
    – Ron Trunk
    Commented Jun 9, 2020 at 13:44
  • Part of the problem is that I cannot ping the ip except from the switch where it resides. However, I get no reply when I remove the camera. There are no static routing tables nor ARP entries.
    – Rob Gates
    Commented Jun 9, 2020 at 13:48

2 Answers 2

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To find a duplicate IP address:

  1. Run a packet capture (possibly filtered by arp).
  2. Ping the address to prompt an ARP request. Ignore the actual ping reply.
  3. Both devices should reply to the ARP request.
  4. Look up the rogue MAC address from step 3 on your switch and follow the associated port to the next switch or to the actual host.

[EDIT] Both server and camera are on the same VLAN 3, so there's no routing involved. Make sure that all three switches see the camera MAC and associate it with the correct port/trunk (I'm not sure which ports/trunks are used to link the switches).

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  • I ran a filter of arp.duplicate-address-frame in wireshark on all interfaces....Then pinged the ip from 2 different servers. I got no returns
    – Rob Gates
    Commented Jun 8, 2020 at 20:17
  • You don't need a ping reply, just capture the ARP replies.
    – Zac67 ♦
    Commented Jun 9, 2020 at 6:29
  • I understand. That is what I was referring to. I got no returns with the filter I used. I dont think that there is a duplicate IP. It just is symptomatic of that. I think that Switch 1 is blocking that IP for some reason. It is the Layer 3 switch that handles the routing.
    – Rob Gates
    Commented Jun 9, 2020 at 13:01
  • Well, there's nothing obvious in Switch1's config that causes any filtering. If communcation fails, check the local or the gateway's ARP table to make sure the MAC is correct. If it isn't you need to find out why. If it is, trace back how far the packets make it, using port mirroring and packet capture.
    – Zac67 ♦
    Commented Jun 9, 2020 at 15:16
  • Switch 5 > Etherchannel group 1 to Ether channel group 3 on Switch 1. Switch 2 > Etherchannel group 1 to Ether channel group 2 on Switch 1 I agree, It is not a routing issue. What would prevent/block and IP address? I have the same type of camera in port 5 of Switch 2 that works fine and is reachable from all swtiches. However when I give it the address of 192.168.28.60 it is no long reachable
    – Rob Gates
    Commented Jun 9, 2020 at 16:33
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After much confusion, I decided to just reboot Switch 1. It has been running for about 5 years, so it was due a reload. This fixed my problem. It would be nice to figure out why this happened. I suppose that something got corrupted somewhere. Thank you for all of your help.

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