NXC2500 issue with MikroTik DHCP

siddx Posts: 4
Friend Collector First Comment
edited May 21 in Wireless

Hello, we moved from MikroTik (MT) wireless solution to NXC2500 + NWA5121-N/NWA5123-AC APs and have troubles with it

Topology is: MT as main router, NXC2500 and 15 APs connected to one (not default) VLAN (untagged VLAN configured on switches as access ports, not on NXC2500, they think that they are in untagged VLAN)

Static IP addresses on NXC2500 and APs configured in web interface, static ARP entries for them configured on MT to ensure that they always have L2 and L3 layers between each other

Randomly (once a week, once a month or once a day) stations stop receiving IP addresses from MT DHCP server (log spamming "dhcp offering lease IP for MAC without success", different stations, not one), its not MT fault, because rebooting NXC2500 fixes this until next time

Double checked all trunk/access ports, it all configured fine, so I think that switches are ok

Tried enabling always broadcast on DHCP server - didn't help with issue

The questions:

  1. What is this? Have you seen this before, maybe you have any guess about what can cause this issue?
  2. Can it be hardware issue?
  3. If nothing helps, we are going to change NXC2500 to another one that we have already - how can we move license on "+8 APs" from one NXC2500 to another?

All Replies

  • Alfonso
    Alfonso Posts: 257  Master Member
    First Anniversary Friend Collector First Answer First Comment

    Hi @siddx

    It looks a complex issue.

    I suggest to get packet traces using a sniffer and open a ticket to support team (attaching the packet traces).


  • siddx
    siddx Posts: 4
    Friend Collector First Comment
    edited November 2019

    I'll try to do it

  • GreenPuzzle
    GreenPuzzle Posts: 30  Freshman Member
    First Anniversary 10 Comments Friend Collector First Answer

    Could you please provide the topology so that we can further check what could go wrong with the traffic? Such as how AP,NXC,Switch and MT Getaway(DHCP Server) connected to each other. Also, does the SSID use different VLAN from management VLAN ?

    So base on your statement, you can try things below:

    1. Capture packets of DHCP negotiation(Discover-Offer-Request-Ack), and check where and which packet is dropped.
    2. Check the leased IP from Gateway, is it already used by other device with static IP?
    3. When the station fails to get IP address from DHCP Server, can they access the Internet with static IP address?

    Just like Alfonso said, we need more information to clarify the symptom and find the root cause.

    Best Regards and hope to hear your update soon :)