I'm rather new, but quickly becoming familiar with, Linux.

We recently had an issue with a server we had co-located at a local ISP. For 3 weeks people outside our LAN and the regional TW Roadrunner network were unable to connect to this server.

The problem turned out to be a problem with the hosts.allow file. Apparently, as the TS guy in our office eloquently put it, 'the first line in the hosts.allow file somehow got clobbered."

This line happened to be
in.ftp:All

Apparently the 'in.' portion was missing.

More lines below were set up to specifically allow access to our LAN and twcny.rr,com, explaining why we could access it but the rest of the world could not.

My question is this:

is there any way this line could accidentally be 'clobbered' unless you were logged in as root and specifically modifying the hosts.allow file?

TIA for any insight.

You have to have root-permissions to do that!
Okay, there are programms like portsentry that can change your host.deny, but not your host.allow.
So, it looks to me like someone did some misconfiguration on that file ;-)