Bounced email to my domain

[Jeffrey S. Sims]

I was just notified by someone that an email addressed to a user at my company bounced back with the following message:

The following recipient(s) could not be reached:

'username@domain.org' on 8/7/2002 12:57 PM
One or more mandatory argument(s) were missing from the
recipient
The MTS-ID of the original message is: c=US;a=tsa-hp;p=TSA
Inc.;l=VIPER_01-020807155617Z-177

(username@domain.org is where the valid email address is listed in the bounce, I changed it in this posting for security reasons)

This is coming from someone outside with a different company. All other emails are working correctly both internal and external. I can receive emails from as well as send emails to other businesses or outside addresses. The "To:" email address (I changed it in the example above) is correct and functioning correctly. I was wondering what could this person's server be looking for that is not being provided by my server. I am running Sendmail 8.11

Any help would be appreciated.

[Hai Nguyen_1]

Can you ping domain.org from your mail server?

Hai

[Jeff Schussele]

Hi Jeff,

I'd ask them to send you the entire msg - including ALL headers involved. Have them dump this into a file & attach it to an e-mail to you. You NEED to know just *where* the mail is being bounced. It's entirely possible that their outbound mail server is bouncing it back to their user before it even leaves their domain.

It's always good practice to keep an "outside" address available from within the company to "test" these addresses. Say you have a yahoo account. Go out to it & send an e-mail to your user & see if it's delivered. If it is there's a 99.999% chance the problem is entirely theirs.

Rgds,
Jeff

[Zafar A. Mohammed_1]

It seems the destination address is blocked to receive the incoming mails.

[Jeffrey S. Sims]

Jeff,

After looking at their logs and my logs it appears that my server rejected it because it could not resolve the domain name. The log entry is:

Aug 8 10:04:52 my_servername sendmail[14775]: g78H4qm14775: ruleset=check_mail, arg1
=, relay=[207.141.97.70], reject=451 4.1.8 ... D
omain of sender address username@tsa.com does not resolve

(Where my_servername is the name of my email server and username@tsa.com is substituting for the actual username)

The dig output for this domain is as follows:

$ /opt/dig/bin/dig tsa.com mx

; <<>> DiG 2.0 <<>> tsa.com mx
;; ->>HEADER<<- opcode: QUERY , status: NOERROR, id: 6
;; flags: qr aa rd ra ; Ques: 1, Ans: 1, Auth: 0, Addit: 1
;; QUESTIONS:
;; tsa.com, type = MX, class = IN

;; ANSWERS:
tsa.com. 3600 MX 1 mail.tsa.com.

;; ADDITIONAL RECORDS:
mail.tsa.com. 3600 A 207.141.97.70

;; Sent 1 pkts, answer found in time: 121 msec
;; FROM: spectra2 to SERVER: default -- 0.0.0.0
;; WHEN: Fri Aug 9 14:02:40 2002
;; MSG SIZE sent: 25 rcvd: 62

Since it finds a mx server using dig there is no reason it should not be able to resolve the name as far as I know. Any suggestions or further help would be appreciated. Thanks in advance.

SimsJS

[Jeff Schussele · Accepted solution]

Hi (again) Jeff,

Unless you've modified sendmail to use a different DNS lookup method, it just uses the standard nslookup utility.

So I'd nslookup (type MX) on the domain & then if it returns an MX server for the domain, I'd take the next step of doing nslookup on that server. If it returns an IP address, then nslookup that as well - that's a reverse lookup.
SendMail requires that the reverse lookup succeed as well - mainly to foil spoofed domain/host names.

If they all come back OK AND the user can now receive mail OK from that domain, I'd chalk it up to a DNS "glitch" at the time that mail was rec'd. It happens...DNS ain't guaranteed...the primary may have been down & the backup wasn't up-to-date, heck their domain entry could have very well been off-line at that time. It's something you have no control over.

Tell your user that if it's important mail & it's not delivered in the normal time frame, they need to call the sender to have them resend. Or at least contact you so you can investigate real-time.

Rgds,
Jeff

[Jeffrey S. Sims]

Jeff, you are indeed "The Man". The reverse lookup for the IP address didn't work. I will notify them and have them fix it. Thanks for the help. This was starting to bug me.

I got the user their email by having the sender send it to my personal address and I then forwarded it to them so that wasn't an issue. I just don't like something going on like that that I can't really explain other than to say that they may be having problems on their end.

Thanks for your help, now I can sleep at night.

SimsJS