Invalid Domain message

Hi,

For some reason we have been getting a lot of failed
deliveries like this.

Reporting-MTA: dns; ehowe.com

Final-Recipient: rfc822;tim_fosterpg.com
Action: failed
Status: 5.0.0
Diagnostic-code smtp; Invalid Domain (pg.com)

I did the nslookup but don't really understand what it's
telling me.
Would this be a problem with my surgemail configuration or
the dns server.
I haven't changed a thing on our mail server and it's been
humming along 
nicely
for a while.

 > nslookup
Server:         64.132.94.250
Address:        64.132.94.250#53

** server can't find nslookup: NXDOMAIN
 > set type=mx
 > pg.com
Server:         64.132.94.250
Address:        64.132.94.250#53

Non-authoritative answer:
pg.com  mail exchanger = 10 bdc-edge02.na.pg.com.
pg.com  mail exchanger = 10 bdc-edge03.na.pg.com.
pg.com  mail exchanger = 10 edc-edge01.eu.pg.com.
pg.com  mail exchanger = 10 bdc-edge01.na.pg.com.

Authoritative answers can be found from:
pg.com  nameserver = ns01.savvis.net.
pg.com  nameserver = ns03.savvis.net.
pg.com  nameserver = ns02.savvis.net.
pg.com  nameserver = ns04.savvis.net.
pg.com  nameserver = ns05.savvis.net.
bdc-edge02.na.pg.com    internet address = 192.44.184.14
bdc-edge03.na.pg.com    internet address = 192.44.184.207
edc-edge01.eu.pg.com    internet address = 143.19.70.13
bdc-edge01.na.pg.com    internet address = 192.44.184.17
ns02.savvis.net internet address = 204.70.57.242
ns01.savvis.net internet address = 204.70.128.1
ns05.savvis.net internet address = 204.71.116.25
ns04.savvis.net internet address = 204.70.49.234
ns03.savvis.net internet address = 204.70.25.234

Thanks for any insight.
Randy Zumwalde

Randy Zumwalde wrote:
> Hi,
>
> For some reason we have been getting a lot of failed
deliveries like
> this.
>
> Reporting-MTA: dns; ehowe.com
>
> Final-Recipient: rfc822;tim_fosterpg.com
> Action: failed
> Status: 5.0.0
> Diagnostic-code smtp; Invalid Domain (pg.com)
>
> I did the nslookup but don't really understand what
it's telling me.
> Would this be a problem with my surgemail configuration
or the dns
> server.
> I haven't changed a thing on our mail server and it's
been humming
> along nicely
> for a while.
>
> > nslookup
> Server:         64.132.94.250
> Address:        64.132.94.250#53
>
> ** server can't find nslookup: NXDOMAIN
> > set type=mx
> > pg.com
> Server:         64.132.94.250
> Address:        64.132.94.250#53
>
> Non-authoritative answer:
> pg.com  mail exchanger = 10 bdc-edge02.na.pg.com.
> pg.com  mail exchanger = 10 bdc-edge03.na.pg.com.
> pg.com  mail exchanger = 10 edc-edge01.eu.pg.com.
> pg.com  mail exchanger = 10 bdc-edge01.na.pg.com.
>
> Authoritative answers can be found from:
> pg.com  nameserver = ns01.savvis.net.
> pg.com  nameserver = ns03.savvis.net.
> pg.com  nameserver = ns02.savvis.net.
> pg.com  nameserver = ns04.savvis.net.
> pg.com  nameserver = ns05.savvis.net.
> bdc-edge02.na.pg.com    internet address =
192.44.184.14
> bdc-edge03.na.pg.com    internet address =
192.44.184.207
> edc-edge01.eu.pg.com    internet address =
143.19.70.13
> bdc-edge01.na.pg.com    internet address =
192.44.184.17
> ns02.savvis.net internet address = 204.70.57.242
> ns01.savvis.net internet address = 204.70.128.1
> ns05.savvis.net internet address = 204.71.116.25
> ns04.savvis.net internet address = 204.70.49.234
> ns03.savvis.net internet address = 204.70.25.234
>
> Thanks for any insight.
> Randy Zumwalde
>
Before accepting email, surgemail(and many other MTA's) will
check to
make sure that the domain in the From and Reply-to fields
really exist
on the Internet.  That check is failing on your mail server
and your
server will tell the other mail server that we don't want
your email
because we have reason to believe the email address don't
exist.

You stated that you are getting alot of failures like this. 
That would
indicate dns failures.  Not knowing your infrastructure,
makes it hard
to troubleshoot.  The name servers your email server is
querying could
be overloaded.  Your mail server could be overloaded and
it's missing
the replies.  Or your mail servers Internet connection is
overloaded and
the dns traffic gets lost on the way out or on it's way back
into your
network.

The above replies from NSLOOKUP look normal.  If you use dig
instead for
these queries, dig gives you the amount of time it took to
get the reply
back from the name server being queried.  That information
would be
usefull in troubleshooting this issue.

Lyle Giese
LCR Computer Services, Inc.