Conntrac tftp appears to be failing (and udp conntrack in general)

[Netboy3]

This seems to be an issue with conntrack helpers in general with VyOS 1.4. I’m experiencing the same issue with TFTP, and there’s another thread regarding similar issue with FTP (which also requires a helper).

@wildcarde

I’ve also tried replacing the nat with a port forward so when clients attempt to hit their gateway IP at port 69 it forwards to the appropriate server. this unfortunately has also failed.

Unfortunately, that’s not how TFTP works. You can’t just forward it as is because in addition to UDP/69 it uses a random port for the data channel - which is why the helper module is needed.

@wildcarde

The nat entry gets created:

AFAIK, helper modules add their temporary entries in the conntrack “expectations” table which you can view using conntrack -L expect. Unfortunately, I wasn’t able to see anything, indicating again that something is wrong with the conntrack helpers.