Hi there. I faced a problem recently. SVI of my switch doesn’t get IP-address via DHCP server on my Mikrotik 951Ui-2nD (6.42.1). Although it gets IP-address via ISC-DHCP server. I’ve watched the log but can’t find the reason of NAK. How can I do that?
P.S. Attached log from mikrotik.
2200.txt (3.59 KB)
Best way I use is to grab comuniaction into file.cap and analyze it in WireShark .
Tools > Sniffer your friend.
I already did that. In the pcap-file you cannot see the reason of NAK.
For analysis you should post the output of this CLI command on the router:
/ip export hide-sensitive
or redirect the output to a file and download the file from the /Files area and post its content:
/ip export hide-sensitive file=ip-export-hs
I’ve done that but still can’t see the reason of NAK. It only shows some settings.
No, you may have done the export but you have not posted it on the forum for us to see what you did!
However, it is not very likely that this will solve the problem. It is wellknown that there are some cases where a client (which does not behave well) does not get an IP address from the MikroTik DHCP server while it has no problem getting one from other servers.
It might help when you post the wireshark decode (all fields unfolded) of a single DHCP exchange here.
You can use tshark (the commandline version) with the -V flag to get a comprehensive decode of the entire packet (one packet outputting like 100 lines).
So post only the 3-4 packets of a single exchange.