Chrissy, I expect that you will always get this response, it is common for the domain not to have an IP address, after all, which machine should it tell you about? If you tried www.bebe.com, you will probably get an IP address as that will translate to an actual machine. Sendmail will always assume MX records as these are all that is relevant to it. Why should sendmail worry about the web or FTP address ;-) Alan

---------- From: Chrissy LeMaire[SMTP:chrissy@netnerds.net] Sent: 21 March 2000 18:06 To: suse-security@suse.com Subject: [suse-security] sendmail -- sender domain must resolve

Hey All, I'm running sendmail 8.9.3 and pretty much left everything default. The spam stoppers are in full effect..

I have a question about the following:

Mar 20 14:39:25 xxx sendmail[18726]: OAA18726: ruleset=check_mail, arg1=, relay=[111.111.111.111], reject=451 ...

Sender domain must resolve

So i do a bit of digging:

# nslookup

...

bebe.com Server: ns.server.com Address: ip.addy.here

*** ns.server.com can't find bebe.com: Non-existent host/domain

...

set type=mx bebe.com Server: ns.server.com Address: ipaddyhere

Non-authoritative answer: bebe.com preference = 0, mail exchanger = bebe-mail.bebe.com

Authoritative answers can be found from: bebe.com nameserver = AUTH02.NS.UU.NET bebe.com nameserver = bebe-ns.bebe.com bebe.com nameserver = BEBE-NS2.bebe.com bebe-mail.bebe.com internet address = 208.240.224.197 AUTH02.NS.UU.NET internet address = 198.6.1.82 bebe-ns.bebe.com internet address = 208.240.224.225 BEBE-NS2.bebe.com internet address = 208.240.224.210

By looking at this.. I concluded that MX records aren't looked at when deciding if a domain resolves or not. So.. I do the some testing with hospitalforms.com (which doesnt resolve but has an MX record) and it worked..

So. Am I right when I assume that bebe.com's ns servers were most likely down for a period of time? Auth02.ns.uu.net is huge.. and 3 nameservers all go down at the same time?

This doesnt seem right.

Any suggestions?

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