Thanks to everyone who has replied so far. I am perplexed as to why some people are not finding my server and some are not. I have had no down time or connection loss during this period, although I can't speak for my secondary DNS provider. I've verified that both TCP and UDP packets on port 53 are making it through my firewall. I think I will turn up the logging on DNS queries and see if there are any clues there. As for Bill's comments, I would point out that kamps.ca is actually a secondary MX. As for his reverse DNS PTR issue, you are right, the domains differ, although I am not aware of a requirement that they match, only that reverse DNS resolve to something. In any case, I've dropped any secondary MX, and I've moved my secondary DNS to twisted4life. The ttl for my records was three days so anyone who has checked against me recently will have stale cache entries, but the root servers appear to have up-to-date DNS records for me, so anyone new who cares to try should get new records. Thanks again for the help! Michael On February 4, 2006 07:04 am, Bill Strosberg wrote: > Michael Walma wrote: > > Hello All: > > > > I have an odd problem where some sites are refusing to accept mail from > > me. 99% of sites will accept mail from me, a but a few reject mail with > > the following response: > > I get the following: > > bill@laptop:~$ nslookup > > > set q=mx > > walma.org > > Server: 192.168.2.1 > Address: 192.168.2.1#53 > > Non-authoritative answer: > walma.org mail exchanger = 100 kamps.ca. > walma.org mail exchanger = 10 walma.org. > > Authoritative answers can be found from: > walma.org nameserver = ns.kamps.ca. > walma.org nameserver = ns1.walma.org. > kamps.ca internet address = 66.11.174.116 > walma.org internet address = 64.26.160.120 > ns.kamps.ca internet address = 66.11.174.116 > ns1.walma.org internet address = 64.26.160.120 > > > set q=ns > > walma.org > > Server: 192.168.2.1 > Address: 192.168.2.1#53 > > Non-authoritative answer: > walma.org nameserver = ns.kamps.ca. > walma.org nameserver = ns1.walma.org. > > Authoritative answers can be found from: > ns.kamps.ca internet address = 66.11.174.116 > ns1.walma.org internet address = 64.26.160.120 > > But, note the following: > > bill@laptop:~$ host 66.11.174.116 > 116.174.11.66.in-addr.arpa domain name pointer pi314159.ott.istop.com. > > Your primary mail exchanger box (kamps.ca) does not handle reverse DNS > lookups properly. You (actually the kamps.ca tech contact) will > probably have to contact Cybersurf to get them to edit the in-addr-arpa > record for 66.11.174.116 to get this to resolve properly. > > -- > Bill Strosberg