Weird network errors
News ·Thursday November 9, 2006 @ 02:20 EST (link)
I temporarily activate an FTP (file transfer) server on minas-tirith (it's usually off because the less services running the better for security, especially as that box is the Internet gateway machine) to transfer an image that I've just scanned and edited in Paint Shop Pro. But I can't connect to the server!
I muddle through diagnosis: am I reaching the FTP server (proftpd)? no; is it reaching the super-server (xinetd)? no; does it reach the FTP server without using the super-server (ServerMode standalone)? no; are the packets coming over the wire (tcpdump)? yes, well, most of the time. Is iptables routing interfering? no; there are no FTP rules, and strangely enough, the auth server (midentd) works. The FTP server also works fine from localhost and another machine. Is the wireless router interfering? I'd like to know, but I can't connect to the administrative interface. Hmm.... I can connect from another machine. And, looks like the wireless router is using the same internal address that the machine I'm connecting from is using. Oops. I'm not sure why this hasn't affected other connections (ssh between the same two machines is fine, as is auth, as I've mentioned); could be the wireless router is sending some sort of quench packet for FTP requests. The address on the router isn't even actually used; I've reconfigured it to act more like a switch than a router, but it must still recognize packets with that address sent over the wire.
Just another fun exciting day in the land of networks. Ha!
