Dumb DNS Problems on Linux
Okay, so I’ve had the most bizarre problems with name resolution on Linux since I moved to SUSE. Okay, well, it’s not actually in terms of resolution. It’s odd. Previous problems aside that I’ve already blogged about, this one is new and recently discovered.
It seems that name lookup is fine and quick. Everything is fine in Mozilla, Konquerer, and just about every other application, including ncftp. But if I try and use telnet to connect to some random ftp server by hostname (ie., telnet ftp.suse.com 21), it takes about 20-30 seconds to establish the connection. Same goes for any service that I try to connect to via the command line using telnet. Or the native ftp client (and as I note, ncftp is also fine).
My network set-up has all DNS going through my NAT box which provides DNS forwarding. This works quite nicely and I haven’t had problems with it in the past. I do note, however, that I’m quite certain that the DNS forwarder included in my cruddy NAT software does not support IPv6 calls, which SUSE tries to spit out, despite it being disabled. This *may* be part of the current problem.
To test it, I booted with Knoppix. Boom. Same problem. This isn’t unique to SUSE. Is it something weird with my NIC? Nope. I booted with Knoppix on my laptop, and the same issue occured.
So I upgraded my NAT software and fiddled a little, and now everything is fine.
The moral of the story? Don’t use old NAT software. No, wait — I’ve got a better one: don’t do NAT on Windows. I’m still doing it on Windows because I need that box to run Windows for various legacy hardware I run off it. But I seem to have fixed the problem.
Okay. That’s my ramble. No more.
