Mail loops back to me (MX problem?) - Linux Setup, Configuration & Administration

[Kejpa]

Hi all,
when trying to send mail to [email]kejpakejpa.com[/email] I get the error Mail loops
back to me (MX problem?).
When I use "mail kejpa" it's working, the problem is when using a
external mailclient.

Doing host -t mx kejpa.com gives
kejpa.com mail is handled (pri=20) by 213.204.63.63
213.204.63.63 is the current IP of my machine

I'm a bit confused when doing a telnet 213.204.63.63 25 since I'm told
that I'm on gandalf.kejpa.com not just kejpa.com

Could this be the cause of the problem?
There is no record for gandalf.kejpa.com

Any help is appreciated
/Kejpa

[Timo Voipio]

Kejpa wrote:

> Doing host -t mx kejpa.com gives
> kejpa.com mail is handled (pri=20) by 213.204.63.63
> 213.204.63.63 is the current IP of my machine

Hmm. Looks correct.

> I'm a bit confused when doing a telnet 213.204.63.63 25 since I'm told
> that I'm on gandalf.kejpa.com not just kejpa.com

I tried telnetting to kejpa.com:25 and did not see anything.

> Could this be the cause of the problem?

As I see it, the primary problem is that kejpa.com does not accept outside
connections. Perhaps you misconfigured your SMTP server or firewall? Or does
Ålcom block TCP 25 inbound?

-Timo

--
Timo Voipio | Helsinki, Finland | ICBM at: 60 11.800 N 024 52.760 E
GeekCode ver 3: GU>CC d s-: a--- C++ UL(+)$>+++$ P+>+++ L++(+) E- W++ N++
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Remove +newsharvested to e-mail me | Poista +newsharvested jos meilaat

[David Efflandt]

On Wed, 06 Aug 2003 15:03:11 +0300, Kejpa <kejpanetscape.net> wrote:

> Hi all,
> when trying to send mail to [email]kejpakejpa.com[/email] I get the error Mail loops
> back to me (MX problem?).
> When I use "mail kejpa" it's working, the problem is when using a
> external mailclient.
>
> Doing host -t mx kejpa.com gives
> kejpa.com mail is handled (pri=20) by 213.204.63.63
> 213.204.63.63 is the current IP of my machine
>
> I'm a bit confused when doing a telnet 213.204.63.63 25 since I'm told
> that I'm on gandalf.kejpa.com not just kejpa.com
>
> Could this be the cause of the problem?
> There is no record for gandalf.kejpa.com

Is gandalf.kejpa.com your FQDN hostname or in /etc/hosts (it does not
resolve in public DNS)? I cannot 'telnet 213.204.63.63 25' (no response),
what response do you get for that from outside of your system? And
traceroute gets no her than 17 * core-7-ge00.alcom.aland.fi
(194.112.1.242) 151 ms 150 ms (maybe blocked by your firewall).

Since your computer may think it is gandalf.kejpa.com, have you configured
your smtp server with kejpa.com in the list of hosts/domains it receives
mail for (which smtp server/version)? What do your mail logs say?

--
David Efflandt - All spam ignored [url]http://www.de-srv.com/[/url]
[url]http://www.autox.chicago.il.us/[/url] [url]http://www.berniesfloral.net/[/url]
[url]http://cgi-help.virtualave.net/[/url] [url]http://hammer.prohosting.com/~cgi-wiz/[/url]

[Ian Northeast]

Kejpa wrote:

>
> Hi all,
> when trying to send mail to [email]kejpakejpa.com[/email] I get the error Mail loops
> back to me (MX problem?).
> When I use "mail kejpa" it's working, the problem is when using a
> external mailclient.
>
> Doing host -t mx kejpa.com gives
> kejpa.com mail is handled (pri=20) by 213.204.63.63
> 213.204.63.63 is the current IP of my machine
>
> I'm a bit confused when doing a telnet 213.204.63.63 25 since I'm told
> that I'm on gandalf.kejpa.com not just kejpa.com
>
> Could this be the cause of the problem?
> There is no record for gandalf.kejpa.com

You seem to have three problems, two of which have already been pointed
out:

Your mail server is unreachable from the outside world;

Your mail exchange software has not been configured to accept mail for
kejpa.com;

Your MX record has a value which is an IP address. This is wrong, it
should be another name which in turn should be the label on an A record
which has a value of the address. This will cause some remote mail
exchanges to be unable to send you mail.

Has your ISP given you a static address? Your range is described as "DSL
customer segment. DHCP addressing" which suggests not. If your address
changes your mail will stop working (assuming it starts).

Regards, Ian

[Xyerp]

Kejpa <kejpanetscape.net> wrote in message news:<3F30EE7F.9020008netscape.net>...

> Hi all,
> when trying to send mail to [email]kejpakejpa.com[/email] I get the error Mail loops
> back to me (MX problem?).
> When I use "mail kejpa" it's working, the problem is when using a
> external mailclient.
>
> Doing host -t mx kejpa.com gives
> kejpa.com mail is handled (pri=20) by 213.204.63.63
> 213.204.63.63 is the current IP of my machine
>
> I'm a bit confused when doing a telnet 213.204.63.63 25 since I'm told
> that I'm on gandalf.kejpa.com not just kejpa.com
>
> Could this be the cause of the problem?
> There is no record for gandalf.kejpa.com
>
> Any help is appreciated
> /Kejpa

Yup. Looks like a mail exchanger record problem.

This question has been asked thousands of times before. So much so
that there is even an answer to this question in the FAQ for sendmail.

If you can

1.) Read the FAQ
2.) Supply information regarding the software you are using

that may be handy?

[Kejpa]

Hi there!
Back after some vacation.
Thanx for your efforts, I realized that I didn't accept connections on
port 25 from the outside. I'd fixed that now.
However my problem is still there, "Mail loops back to me". Postmaster
gets the mail but it's not delievered to the user accounts.

To David: gandalf.kejpa.com is the name of my server. From what I've
understood it's not supposed to be in the public DSN.

To Ian: No, I don't have a static address. My DNS records are handled by
EveryDNS.org, they will be notified about the IP number whenever my
computer starts and on a schedule when it's up running.

To Xyerp: I have RTFM and I have looked at the FAQ, but I'm still in
limbo. Software wise I have RH9 with Sendmail 8.12.8, what else do you
need to know?

Regards
/Kejpa

[Bill Unruh]

Kejpa <kejpanetscape.net> writes:

]Hi there!
]Back after some vacation.
]Thanx for your efforts, I realized that I didn't accept connections on
]port 25 from the outside. I'd fixed that now.
]However my problem is still there, "Mail loops back to me". Postmaster
]gets the mail but it's not delievered to the user accounts.

]To David: gandalf.kejpa.com is the name of my server. From what I've
]understood it's not supposed to be in the public DSN.

]To Ian: No, I don't have a static address. My DNS records are handled by
]EveryDNS.org, they will be notified about the IP number whenever my
]computer starts and on a schedule when it's up running.

]To Xyerp: I have RTFM and I have looked at the FAQ, but I'm still in
]limbo. Software wise I have RH9 with Sendmail 8.12.8, what else do you
]need to know?

We need to know how you have sendmail set up. What is the mail address
of your system. What are the various entries in sendmail.cf What is your
local delivery agent (procmail) You get this message when you machine
tries to forward the mail to another mail address, which it discovers is
the current machine. Eg I had this problem when I told the system to
deliver mail to theory.physics.ubc.ca to string.physics.ubc.ca when they
are the same system, and I had not told the mta that they were the same.
ie you may have to put in an entry telling the system what all the names
of the local machine are.

[Kjell Hansen]

Hey there,
thanx for you time, Bill.

> We need to know how you have sendmail set up.

I'm attaching the effective lines from my m4 config file at the bottom
of this mail.

> What are the various entries in sendmail.cf

I have the standard entries there along with a handful for my accounts

> What is your local delivery agent (procmail)

I don't think I have one, at least haven't I configured any procmail.
From what I've understood, SendMail is capable of distributing mail
locally.

I can send mail locally and I can send mail from the server but when I
try to send to an account on the server I get this error.
You can try it by sending to [email]kejpakejpa.com[/email] the sender will be notified
aswell as postmaster. (I'm not too happy about that postmaster address
being [email]postmastergandalf.kejpa.com[/email], I'd prefer just [email]postmasterkejpa.com[/email])

How do I tell the MTA that mail destined for kejpa.com is to be handled
by gandalf.kepja.com?

Will just setting kejpa.com as an alias for gandalf.kejpa.com in the
hosts file do?

Regards
/Kejpa

My sendmail.mc file (commented lines have been deleted):
divert(-1)dnl
include(`/usr/share/sendmail-cf/m4/cf.m4')dnl

VERSIONID(`setup for Red Hat Linux')dnl
OSTYPE(`linux')dnl

define(`confDEF_USER_ID',``8:12'')dnl
define(`confTRUSTED_USER', `smmsp')dnl
dnl define(`confAUTO_REBUILD')dnl
define(`confTO_CONNECT', `1m')dnl
define(`confTRY_NULL_MX_LIST',true)dnl
define(`confDONT_PROBE_INTERFACES',true)dnl
define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl
define(`ALIAS_FILE', `/etc/aliases')dnl
define(`UUCP_MAILER_MAX', `2000000')dnl
define(`confUSERDB_SPEC', `/etc/mail/userdb.db')dnl
define(`confPRIVACY_FLAGS', `authwarnings,novrfy,noexpn,restrictqrun')dnl
define(`confAUTH_OPTIONS', `A')dnl
define(`confTO_IDENT', `0')dnl
FEATURE(delay_checks)dnl
FEATURE(`no_default_msa',`dnl')dnl
FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
FEATURE(redirect)dnl
FEATURE(always_add_domain)dnl

FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
FEATURE(`blacklist_recipients')dnl

FEATURE(`accept_unresolvable_domains')dnl
FEATURE(`relay_based_on_MX')dnl
FEATURE(masquerade_envelope)dnl
FEATURE(masquerade_entire_domain)dnl

LOCAL_DOMAIN(`localhost.localdomain')dnl

MASQUERADE_DOMAIN(kejpa.com)dnl
MASQUERADE_AS(`kejpa.com')dnl


MAILER(local)dnl
MAILER(smtp)dnl

[Bill Unruh]

Kjell Hansen <kjell.hansentelia.com> writes:

]Hey there,
]thanx for you time, Bill.
]> We need to know how you have sendmail set up.
]I'm attaching the effective lines from my m4 config file at the bottom
]of this mail.

]> What are the various entries in sendmail.cf
]I have the standard entries there along with a handful for my accounts

]> What is your local delivery agent (procmail)
]I don't think I have one, at least haven't I configured any procmail.
] From what I've understood, SendMail is capable of distributing mail
]locally.

No. One of the entries in sendmail.cf is the user delivery agent. I have
not worked with sendmail in about 5 years, but recall the lines being
about halfway down.

]I can send mail locally and I can send mail from the server but when I
]try to send to an account on the server I get this error.
]You can try it by sending to [email]kejpakejpa.com[/email] the sender will be notified
]aswell as postmaster. (I'm not too happy about that postmaster address
]being [email]postmastergandalf.kejpa.com[/email], I'd prefer just [email]postmasterkejpa.com[/email])


]How do I tell the MTA that mail destined for kejpa.com is to be handled
]by gandalf.kepja.com?

You tell dns who is to handle the mail. At present mail for kejpa.com is
handled by hst63-63.aland.net, as the only dns MX entry.
I assume that hst63-63.aland.net then sends on mail for kejpa.com to
gandalf.kejpa.com.



]Will just setting kejpa.com as an alias for gandalf.kejpa.com in the
]hosts file do?

Probably not in the hosts file. In the sendmail.cf file.


Hmm. I left sendmail for postfix about the time that the .mc files came
in. The .cf raw files is what I remember editing and there was a line )w
I think it it was) which listed all the aliases for the local machine
(email addresses for which this machine was the recipient).


]My sendmail.mc file (commented lines have been deleted):
]divert(-1)dnl
]include(`/usr/share/sendmail-cf/m4/cf.m4')dnl

]VERSIONID(`setup for Red Hat Linux')dnl
]OSTYPE(`linux')dnl

]define(`confDEF_USER_ID',``8:12'')dnl
]define(`confTRUSTED_USER', `smmsp')dnl
]dnl define(`confAUTO_REBUILD')dnl
]define(`confTO_CONNECT', `1m')dnl
]define(`confTRY_NULL_MX_LIST',true)dnl
]define(`confDONT_PROBE_INTERFACES',true)dnl
]define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl

Notice this statement. It is what tells sendmail to hand off local
delivery to procmail


]define(`ALIAS_FILE', `/etc/aliases')dnl
]define(`UUCP_MAILER_MAX', `2000000')dnl
]define(`confUSERDB_SPEC', `/etc/mail/userdb.db')dnl
]define(`confPRIVACY_FLAGS', `authwarnings,novrfy,noexpn,restrictqrun')dnl
]define(`confAUTH_OPTIONS', `A')dnl
]define(`confTO_IDENT', `0')dnl
]FEATURE(delay_checks)dnl
]FEATURE(`no_default_msa',`dnl')dnl
]FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
]FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
]FEATURE(redirect)dnl
]FEATURE(always_add_domain)dnl

]FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
]FEATURE(`blacklist_recipients')dnl

]FEATURE(`accept_unresolvable_domains')dnl
]FEATURE(`relay_based_on_MX')dnl
]FEATURE(masquerade_envelope)dnl
]FEATURE(masquerade_entire_domain)dnl

]LOCAL_DOMAIN(`localhost.localdomain')dnl

You could try adding kepja.com to this LOCAL_DOMAIN definition. Looking
at the sendmail.cf of a friends machine (the mc file is not there) there
is also the Fw which is file listing the names of hosts for which we
recieve mail. which seems to be /etc/mail/local-host-names
so try putting it in there.





]MASQUERADE_DOMAIN(kejpa.com)dnl
]MASQUERADE_AS(`kejpa.com')dnl


]MAILER(local)dnl
]MAILER(smtp)dnl

[Xyerp]

Kejpa <kejpanetscape.net> wrote in message news:<3F3E7D9E.1040902netscape.net>...

> Hi there!
> Back after some vacation.
> Thanx for your efforts, I realized that I didn't accept connections on
> port 25 from the outside. I'd fixed that now.
> However my problem is still there, "Mail loops back to me". Postmaster
> gets the mail but it's not delievered to the user accounts.
>
> To David: gandalf.kejpa.com is the name of my server. From what I've
> understood it's not supposed to be in the public DSN.
>
> To Ian: No, I don't have a static address. My DNS records are handled by
> EveryDNS.org, they will be notified about the IP number whenever my
> computer starts and on a schedule when it's up running.
>
> To Xyerp: I have RTFM and I have looked at the FAQ, but I'm still in
> limbo. Software wise I have RH9 with Sendmail 8.12.8, what else do you
> need to know?
>
> Regards
> /Kejpa

From the special sendmail faq/rtfm section:

"
Error message means that <hub> is primary mail handler for <host>.
And there isn't special rules for handling mail to <host> it
sendmail.cf.
And therefore rules of sendmail.cf select SMTP -mailer again. And
MX -records tell that SMTP -mailer to should connect to itself. That
is error condition.

There is several solutions, depends what you actually want.
A) Tell that mail to <host> is local mail to <hub>
A1) Add <host> to class 'w'
A1a) Cw -command
A2b) FEATURE(use_cw_file) /etc/sendmail.cw (or was feature
name this?)
A3c) Fw -command
A2) Special rules in sendmail.cf
B) Pass mail to other mailer (that (E)SMTP mailer)
A1) FEATURE(mailertable) /etc/mailertable
A2) Special rules in sendmail.cf
C) Bypass MX -records (and pass mail to (E)SMTP mailer)
A1) FEATURE(mailertable) /etc/mailertable
A2) Special rules in sendmail.cf
A3) use option 'w' : Ow -command (configuration errors can lead
to 'host unknown' or 'message timed out' -errors instead
that 'MX records points back to' -message.
"

(Applies to a slightly older version of sendmail, check manual for
updates where applicable).