Recently my wife received an Email addressed from jdavidson4@home.com. When she tried to reply to the original message her reply bounced with
----- The following addresses had permanent fatal errors ----- jdavidson4@home.com (reason: 553 5.3.5 system config error)
----- Transcript of session follows ----- 553 5.3.5 home.com.nurdog.com. config error: mail loops back to me (MX problem?) 554 5.3.5 Local configuration error
I started to do some digging and discovered that there is no MX record for home.com which is the ultimate reason my wife's message bounces. However what disturbs me is that given the lack of DNS MX record for home.com my Email server is tacking my domain name nurdog.com onto the original domain name and creating home.com.nurdog.com. I verified that this action is indeed occurring:
# sendmail -bt -C./sendmail.cf ADDRESS TEST MODE (ruleset 3 NOT automatically invoked) Enter <ruleset> <address>
3,0 jdavidson4@home.com
canonify input: jdavidson4 @ home . com Canonify2 input: jdavidson4 < @ home . com > Canonify2 returns: jdavidson4 < @ home . com . nurdog . com . > canonify returns: jdavidson4 < @ home . com . nurdog . com . > parse input: jdavidson4 < @ home . com . nurdog . com . > Parse0 input: jdavidson4 < @ home . com . nurdog . com . > Parse0 returns: jdavidson4 < @ home . com . nurdog . com . > ParseLocal input: jdavidson4 < @ home . com . nurdog . com . > ParseLocal returns: jdavidson4 < @ home . com . nurdog . com . > Parse1 input: jdavidson4 < @ home . com . nurdog . com . > Mailertable input: < home . com . nurdog . com > jdavidson4 < @ home . com . nurdog . com . > Mailertable input: home . < com . nurdog . com > jdavidson4 < @ home . com . nurdog . com . > Mailertable input: home . com . < nurdog . com > jdavidson4 < @ home . com . nurdog . com . > Mailertable input: home . com . nurdog . < com > jdavidson4 < @ home . com . nurdog . com . > Mailertable returns: jdavidson4 < @ home . com . nurdog . com . > Mailertable returns: jdavidson4 < @ home . com . nurdog . com . > Mailertable returns: jdavidson4 < @ home . com . nurdog . com . > Mailertable returns: jdavidson4 < @ home . com . nurdog . com . > MailerToTriple input: < > jdavidson4 < @ home . com . nurdog . com . > MailerToTriple returns: jdavidson4 < @ home . com . nurdog . com . > Parse1 returns: $# esmtp $@ home . com . nurdog . com . $: jdavidson4 < @ home . com . nurdog . com . > parse returns: $# esmtp $@ home . com . nurdog . com . $: jdavidson4 < @ home . com . nurdog . com . >
I run a second server that does not have this problem and this issue only seems to occur on domains with broken DNS. For example if I use an email address which comes with a working server I get:
3,0 prg@cirrus.com
canonify input: prg @ cirrus . com Canonify2 input: prg < @ cirrus . com > Canonify2 returns: prg < @ cirrus . com . > canonify returns: prg < @ cirrus . com . > parse input: prg < @ cirrus . com . > Parse0 input: prg < @ cirrus . com . > Parse0 returns: prg < @ cirrus . com . > ParseLocal input: prg < @ cirrus . com . > ParseLocal returns: prg < @ cirrus . com . > Parse1 input: prg < @ cirrus . com . > Mailertable input: < cirrus . com > prg < @ cirrus . com . > Mailertable input: cirrus . < com > prg < @ cirrus . com . > Mailertable returns: prg < @ cirrus . com . > Mailertable returns: prg < @ cirrus . com . > MailerToTriple input: < > prg < @ cirrus . com . > MailerToTriple returns: prg < @ cirrus . com . > Parse1 returns: $# esmtp $@ cirrus . com . $: prg < @ cirrus . com . > parse returns: $# esmtp $@ cirrus . com . $: prg < @ cirrus . com . >
This obvious thing to try was to remove FEATURE(always_add_domain), run m4 and restart sendmail but that had no effect. I am not that concerned about this problem, but for the life of me googling and comparing the config files between my two Email servers does not indicate anthing obvious to me to cause this behavior. Does anyone have an idea to which sendmail config parameter might be causing nurdog.com to get tacked onto home.com in these circumstances?
Thanks for any ideas.
On Sat, 2006-05-20 at 16:13, Paul R. Ganci wrote:
Recently my wife received an Email addressed from jdavidson4@home.com. When she tried to reply to the original message her reply bounced with
----- The following addresses had permanent fatal errors ----- jdavidson4@home.com (reason: 553 5.3.5 system config error)
----- Transcript of session follows ----- 553 5.3.5 home.com.nurdog.com. config error: mail loops back to me (MX problem?) 554 5.3.5 Local configuration error
I started to do some digging and discovered that there is no MX record for home.com which is the ultimate reason my wife's message bounces.
There is also no A record for home.com. It's going to bounce any way you try it. Comment the: FEATURE(`accept_unresolvable_domains')dnl in sendmail.mc and you won't accept email with bad reply addresses.
Les Mikesell wrote:
There is also no A record for home.com. It's going to bounce any way you try it. Comment the: FEATURE(`accept_unresolvable_domains')dnl in sendmail.mc and you won't accept email with bad reply addresses.
Yes I know I have no hope of ever sending email to that address. The problem is really my wife's perception. It looks like the problem is on my server end when I know it is not.
The FEATURE(`accept_unresolvable_domains')dnl is commented out. My wife received this message because it actually came via a email list which was forwarded from an outside Email server. Since that server accepted the message then my server did too and has to or my wife will shoot me. I would much prefer to see this bounce message which I get from the other email server I run:
----- The following addresses had permanent fatal errors ----- jdavidson4@home.com
----- Transcript of session follows ----- 550 5.1.2 jdavidson4@home.com... Host unknown (Name server: home.com: no data known)
Because then it is obvious where the problem lies even to my wife. I have unwittingly set something on my nurdog.com server and have no clue what.
Les Mikesell wrote:
Comment the: FEATURE(`accept_unresolvable_domains')dnl in sendmail.mc and you won't accept email with bad reply addresses.
As an aside, the original message is legitimate. My wife and I do Alaskan malamute dog rescue. The original message had rescue related material. I suspect the reply-to email address was just wrong in the sender's email client. It is unfortunate because I am sure the people believe we have blown them off, when in reality we just can't contact them.
On Sat, 2006-05-20 at 17:43, Paul R. Ganci wrote:
Comment the: FEATURE(`accept_unresolvable_domains')dnl in sendmail.mc and you won't accept email with bad reply addresses.
As an aside, the original message is legitimate. My wife and I do Alaskan malamute dog rescue. The original message had rescue related material. I suspect the reply-to email address was just wrong in the sender's email client. It is unfortunate because I am sure the people believe we have blown them off, when in reality we just can't contact them.
That's why it's better to not accept it in the first place. If there are no intermediate relays the original sender will get the bounce from his own mailer to let him know about the problem.
On Sat, 2006-05-20 at 16:13, Paul R. Ganci wrote:
Recently my wife received an Email addressed from jdavidson4@home.com. When she tried to reply to the original message her reply bounced with
----- The following addresses had permanent fatal errors ----- jdavidson4@home.com (reason: 553 5.3.5 system config error)
----- Transcript of session follows ----- 553 5.3.5 home.com.nurdog.com. config error: mail loops back to me (MX problem?) 554 5.3.5 Local configuration error
You appear to have a wild-card mx for *.nurdog.com but aren't set up to handle all the possible names. What should happen even if you add your domain to the unresolvable one is that you would still get a 'host not found' from the dns lookup.
Les Mikesell wrote:
You appear to have a wild-card mx for *.nurdog.com but aren't set up to handle all the possible names. What should happen even if you add your domain to the unresolvable one is that
you would still get a 'host not found' from the dns lookup.
Thanks Les I believe I understand now. I don't have a wild-card mx but I think I know where you were going with this. My zone file was originally put together by my ISP:
$ORIGIN nurdog.com. $TTL 5h ; @ IN SOA ns1.mric.net. support.mric.net. ( 2006021901 ; serial 1h ; refresh 30m ; retry 7d ; expiration 1h ) ; minimum ; @ NS ns1.mric.net. @ NS ns2.mric.net.
@ A 204.144.183.66 * A 204.144.183.66
; nurdog.com. IN TXT "v=spf1 a mx a:mail.nurdog.com a:smtp.nurdog.com ~all" @ MX 1 nureyev.nurdog.com.
I never changed anything from the original setup after I took control. With the wild-card A record I will never get a host not found error. Just now I removed the wild card A record and placed only explicit entries for hosts which I know about. Now I get the desired behavior:
# sendmail -bt -C./sendmail.cf ADDRESS TEST MODE (ruleset 3 NOT automatically invoked) Enter <ruleset> <address>
3,0 jdavidson4@home.com
canonify input: jdavidson4 @ home . com Canonify2 input: jdavidson4 < @ home . com > Canonify2 returns: jdavidson4 < @ home . com > canonify returns: jdavidson4 < @ home . com > parse input: jdavidson4 < @ home . com > Parse0 input: jdavidson4 < @ home . com > Parse0 returns: jdavidson4 < @ home . com > ParseLocal input: jdavidson4 < @ home . com > ParseLocal returns: jdavidson4 < @ home . com > Parse1 input: jdavidson4 < @ home . com > Mailertable input: < home . com > jdavidson4 < @ home . com > Mailertable input: home . < com > jdavidson4 < @ home . com > Mailertable returns: jdavidson4 < @ home . com > Mailertable returns: jdavidson4 < @ home . com > MailerToTriple input: < > jdavidson4 < @ home . com > MailerToTriple returns: jdavidson4 < @ home . com > Parse1 returns: $# esmtp $@ home . com $: jdavidson4 < @ home . com > parse returns: $# esmtp $@ home . com $: jdavidson4 < @ home . com >
Thanks for pointing this out ... it was driving me crazy.
-
Les Mikesell -
Paul R. Ganci