Hi All,

We currently use a debian server as our authentication gateway. For each of our clients, they have a DNAT/SNAT record for their connection.

Recently our original server died and we had to switch to a backup, the hard drive from the original server was put into the backup and brought online.

I had to manually update the /etc/udev/rules.d/70-persistent-net.rules file to change the new machine's NIC's back to eth0 and eth1.

Since then, we've had a couple of customers complaining that their FTP is no longer working. Debugging the issue lead back to the DNAT/SNAT mapping.

Since we changed the hard drive into the new server, there's been no software changes between the two system (the original one that died and the backup system); so I can't understand why the FTP is now no longer working.

Is this a common problem with FTP behind DNAT/SNAT or something else?

Thanks
Anubis.

Hi All,

After some more contemplation and research, I've found that the ip_nat_ftp module was not being loaded in the server. I've now ran modprobe ip_nat_ftp and all is working as expected.

My question now is: how can I make this module loading persistent across reboots of the server?

Thanks
Anubis.