You are correct, resolve.conf does list my isp's dns 250.171.3.65 which is qwest. The internal windows workstations also point o the isp's dns server. Can I setup a cashing dns server on the mail server itself??
Absolutely. Assuming that none is running already:
#> netstat -l | grep -e "domain" -e "54"
Should return no results. Now, there are many opinions out there regarding what caching name server to use. I think the easiest here would be BIND. A little bulky, but easily maintained and installed via YUM. Assuming nothing funky with your install, the following should work fine. (you probably have one or many of these installed already)
#> yum install bind bind-utils bind-devel bind-libs caching-nameserver #> /etc/init.d/named start
#> netstat -l | grep -e "domain" -e "54"
Should now show something like: ~]# netstat -l | grep -e "domain" -e "54" tcp 0 0 localhost:domain *:* LISTEN udp 0 0 localhost:domain *:* LISTEN
Now double check that it works: #> dig @127.0.0.1 yahoo.com
If you get a result with Yahoo's IP address info, go ahead and make your server use your new caching name server.
Edit /etc/resolv.conf and add "nameserver 127.0.0.1" to the **TOP** of the list. Leave your ISP's DNS server there just for good measure - you should always have more than one caching DNS server for redundancy. It should now look something like:
#/etc/resolv.conf nameserver 127.0.0.1 nameserver 250.171.3.65 search yourdomainname.com
Feel free to restart your mail server processes if you like, but most should start seeing your new name server right away.
PS: I just wanted to say thanks to everyone who has helped me so far.
No problem. I just hope it helps. I'm running Qmail right now in an ISP setup and had nasty issue about six months ago. Got hit with a double whammy. A bad DNS cache, and a RBL provider timing out and providing poor performance. Gave me similar symptoms.
-Ken