DHCP relay failure post 20.09 update
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I updated my 6100 box from 23.05.1 to 23.09. The upgrade seems to have succeeded; however, DHCP clients all failed until I rebooted to the 23.05.1 boot environment.
I initially checked the DHCP server and everything seemed fine, but the logs did not indicate it receiving the relayed requests.
After a bit more trouble shooting, I did packet traces on both ingress and egress DHCP requests. Ingress requests were being relayed on the egress interface. I compared the relayed egress packets and the only difference I noticed is that the UDP source port is random in 23.09 while in 23.05.1 it is static 67.
I am using Kea for DHCP. It is an external installation that has been up for several years. It is version 2.0.3 and should probably be updated. A search indicated that RFC 8357 allows the source port to be generalized for DHCP relay. I suspect this is the issue that I am running into. I will try to update it in another downtime window.
In the meantime, are there any DHCP Relay options that can be set to revert this behavior?
Best regards.