502 bad gateway with DNS Host Name Resolution failed

I am running NW6.5SP5 with BM3.8 SP4 with BM38SP4_IR3. Since putting on
the updates, two seperate servers with separte internet connections, are
both giving me 502 Bad Gateway errors, with a description of DNS Host
Name Resolution failed.

If I unload IPFLT, one server seems to do OK. The other server still has
the problem although I think it lets me go to a few more sites.

When I go to the server and ping a URL, some URL's will resolve while
others will not. Some of the more popular URL's (like www.novell.com)
will not resolve in the first few tries, but will resolve eventually.
Some less popular URL's don't seem to resolve at all. Once a URL has
resolved, it will resolve imediately every time.

I have unloaded proxy, deleted pxyhosts, and pxyhosts.sav, then loaded
proxy -cc with no change.

Thanks in advance for any advice on where to go from here.