I have a VPS that I am preparing, and ran into a problem that I narrowed down to postfix. If I start with a fresh, minimal Debian 5.01 VPS, do aptitude update, followed by aptitude full-upgrade, everything is fine. I then install postfix ("aptitude install postfix"), and domain name resolution is mostly broken thereafter. I can't ping anything by domain name, but I can ping it by IP address. I say domain name resolution is mostly broken because if I installed dnsutils before postfix, I can still do a dig or nslookup on a name. However, use of domain names seems broken in all other aspects, so the VPS is dead, and if I reboot it, I can't even log in.

It seems odd that postfix would cause the problem. Is there anything I can do to fix it?

what does the contents of /etc/resolv.conf say?

you can test DNS by making a request to the nameserver(s) listed in resolv.conf by using the following:

Resolv.conf contains

nameserver 208.67.220.220


As mentioned, dig resolves the name, but using the name in other contexts will not work. Dig says that www.google.com has addresses 208.67.217.230 and .231. Pinging 208.67.217.230 works fine. Pinging www.google.com hangs.

replied to wrong post - sorry!

is the package resolveconf installed?

Resolvconf wasn't install. I did install it (version 1.42) before installing postfix, but the result is the same as before. It might not be that name resolution is broken, but some how the use of the results is broken.

When I install postfix, the following get installed:

The following NEW packages will be installed:
file{a} libdb4.5{a} libmagic1{a} libsqlite3-0{a} mime-support{a}
openssl{a} openssl-blacklist{a} postfix python{a} python-minimal{a}
python2.5{a} python2.5-minimal{a} ssl-cert{a}

I tried installing the prerequisites, but they don't cause the problem. It is only postfix. As soon as I install the postfix package, I get the problem, and it goes away when I remove the package.