It seems that mail from our servers are going through a third party security mail scanner (offsite),
due the the mx records specified on our internal and external DNS servers.
However, our internal user to user email does not go through the third party security mail scanner.

I discovered that our internal user to user email does not go through the third party security scanner because,
it does not need to. Email clients (outlook, eudora, and etc...) are automatically directed to our
email server, which does not require them to go through DNS and look for an
email server through the MX records.

Our Servers in the other hand, go through the third party security mail scanner.
Our servers still needs to look for an email server through DNS (MX).

I have this error messages every time I try to mailx to myself:

# mailx -v -s 'test mail from server' xnightcrawl@mydomain.com < /tmp/testmail.xnightcrawl.log
# mydomain.com: Name server timeout
xnightcrawl@mydomain.com... Transient parse error -- message queued for future delivery
xnightcrawl@mydomain.com... queued

I think this error is telling me that sendmail is having problems resolving with our DNS setup.
However, I quadruple checked our DNS configuration on the server and it looks okay. nslookup is able
to resolve our mail server, dns server, its own name and IP.

The only discrepancy I found was our external DNS. It does not have the server in question entered in
the database file or an "A" record (zone file), but the internal DNS does.

Please forgive me. I'm new to sendmail and email administration. Any suggestions or ideas will truly be appreciated.