APLawrence.com -  Resources for Unix and Linux Systems, Bloggers and the self-employed

Gateway down-Answer

This is the answer to Gateway Down

This is a classic DNS problem. When I looked at /etc/resolv.conf, it looked like this:


domain xyz.com
nameserver 192.74.xyz.xyz
 

Every time a Windows machine tried to access the Unix box, Unix would do a reverse DNS lookup, using the 192.74 address. If the Internet happened to be down, it would hang a long time trying to get an answer - eventually it would give up, but it was too long for their Windows client application, which effectively just gave up too soon. If the Internet was up, the SCO box would get an immediate "no idea" answer, and would continue quickly. I showed the NT folk that if you were patient enough, telnet would actually connect, but the client application they used just wasn't patient.

This isn't a Unix thing: this would happen with NT or just about any OS I know of; they want to do a reverse DNS lookup when a client connects.

My first thought at fixing this was to make the nameserver point at their internal NT DHCP server which, according to the three NT guys, should provide DNS information for the local network as well as knowing how to get to other nameservers when necessary. However, that didn't work. Not my fault: the NT machine knew nothing about its own DHCP clients. The NT folks were surprised, and said they were sure they could fix it, but that it would take a reboot which was agreed by one and all was Not A Good Idea Right Now.

That's OK, I had another way to fix it. First, I wrote a simple script to populate /etc/hosts, and then modified /etc/resolv.conf to look like this:

domain xyz.com
# local NT DNS server
nameserver 192.168.2.6  
hostresorder local bind
 

That fixed it. We all agreed that the problem should also be fixed at the NT server, but that was their work, not mine.

Publish your articles, comments, book reviews or opinions here!

Copyright May 2001 A.P. Lawrence. All rights reserved



Got something to add? Send me email.





Increase ad revenue 50-250% with Ezoic


More Articles by

Find me on Google+

© Tony Lawrence



Kerio Samepage


Have you tried Searching this site?

Unix/Linux/Mac OS X support by phone, email or on-site: Support Rates

This is a Unix/Linux resource website. It contains technical articles about Unix, Linux and general computing related subjects, opinion, news, help files, how-to's, tutorials and more.

Contact us





A crowded police docket is the surest of all signs that trade is brisk and money plenty. (Mark Twain)

A man can be destroyed but not defeated. (Ernest Hemingway)







This post tagged: