Sendmail problem

Crued · 06-05-2002, 01:53 PM

I'm using Sendmail with my Slackware installation. My problem is that it will not send email to hotmail.com. My outlook client has no problem sending mail to hotmail if i change the outbound smtp server to another server (for example, the one of my dsl provider). When my outbound smtp server is set to my server, the message sits in the outbox forever. In checking /var/log/messages this message shows up for any mail outbound to hotmail

Mar 23 12:44:47 mailer sendmail[168]: g2NIifB00166: to=<user@hotmail.com>, delay=00:00:06, xdelay=00:00:06, mailer=esmtp, pri=33324, relay=mx04.hotmail.com. [64.4.56.135], dsn=2.0.0, stat=Sent (Requested mail action okay, completed)
Mar 23 12:45:40 mailer sendmail[151]: g2NIWVB00151: lost input channel from [myserver local address] to MTA after rcpt
Mar 23 12:45:40 mailer sendmail[151]: g2NIWVB00151: from=<myemail@myserver.net>, size=0, class=0, nrcpts=1, proto=ESMTP, daemon=MTA, relay=[myserver local address]

myserver local address is my server's local IP which is NATed.

All email from/to other servers work as expected.

HELP!

trickykid · 06-05-2002, 05:24 PM

Check with your ISP, they probably don't allow relaying which is basically using another outgoing email server so you would have to continue to use theirs. This prevents SPAM so ISP can monitor what is going out from their customers in most cases.

finegan · 06-05-2002, 05:38 PM

But if it works for addresses other than hotmail...

This is probably a problem with either the Nat'ing or the reverse DNS lookup not matching the reporting domain name... do you have a copy of one of the bounces? It should have gone to root.

Cheers,

Finegan

Crued · 06-07-2002, 08:20 AM

The mail doesn't bounce. It just doesn't go anywhere. You are right in that all mail besides mail to hotmail.com; works fine. I also believe that it's a related to NAT or the reverse DNS, but how to fix?

sewer_monkey · 06-07-2002, 09:30 AM

As a test, try telneting to a hotmail SMTP server (say mx04.hotmail.com, for example) on port 25 and talk to it directly. You'll have to do it from your NATed SMTP server machine, obviously. See what it says. You know, something like this (my input is bolded):

Code:

[rouben@amazon rouben]$ telnet mx04.hotmail.com 25
Trying 64.4.56.135...
telnet: connect to address 64.4.56.135: Connection refused
Trying 65.54.254.129...
Connected to mx04.hotmail.com.
Escape character is '^]'.
220 hotmail.com Microsoft ESMTP MAIL Service, Version: 5.0.2195.4905 ready at  Fri, 7 Jun 2002 07:21:43 -0700
helo
250 hotmail.com Hello [your.ip.address.here]
mail from: user@yourdomain.com
250 user@yourdomain.com....Sender OK
rcpt to: user@hotmail.com
250 user@hotmail.com
data
354 Start mail input; end with <CRLF>.<CRLF>
this is a test
.
250 <blah-blah-blah@hotmail.com> Queued mail for delivery
quit
221 hotmail.com Service closing transmission channel
Connection closed by foreign host.

In this case, I was successful, but I assume you'll be getting an error message. See how talkative Hotmail's servers are, maybe they'll give you a clue as to what is going on. I have highlighted the IP address in red, because I think that's where the problem lies (reverse DNS).

Good luck!

Crued · 06-07-2002, 09:47 AM

Ok, just tested it, and it worked the same as yours did. Checked the account and mail went through properly.

I have a suggestion from another list that reads...

*********************************************
FEATURE(`nocanonify')

That will reduce the number of DNS lookups while accepting the mail from the connecting client.

Your problem appears to be that the client software is impatient, and gives up prematurely. Reducing the time for accepting the message should help.
*********************************************

My sendmail.cf doesn't contain any statements with 'FEATURE', but
I did find

Scanonify=3

** and then a few lines later

# find focus for list syntax
R $+ : $* ; @ $+ $@ $>Canonify2 $1 : $2 ; < @ $3 > list syntax
R $+ : $* ; $@ $1 : $2; list syntax
# find focus for @ syntax addresses
R$+ @ $+ $: $1 < @ $2 > focus on domain
R$+ < $+ @ $+ > $1 $2 < @ $3 > move gaze right
R$+ < @ $+ > $@ $>Canonify2 $1 < @ $2 > already canonical

# do some sanity checking
R$* < @ $* : $* > $* $1 < @ $2 $3 > $4 nix colons in addrs

# convert old-style addresses to a domain-based address
R$- ! $+ $@ $>Canonify2 $2 < @ $1 .UUCP > resolve uucp na$
R$+ . $- ! $+ $@ $>Canonify2 $3 < @ $1 . $2 > domain uucps
R$+ ! $+ $@ $>Canonify2 $2 < @ $1 .UUCP > uucp subdomains

# if we have % signs, take the rightmost one
R$* % $* $1 @ $2 First make them all @s.
R$* @ $* @ $* $1 % $2 @ $3 Undo all but the last.
R$* @ $* $@ $>Canonify2 $1 < @ $2 > Insert < > and finish

# else we must be a local name
R$* $@ $>Canonify2 $1

Crued · 06-07-2002, 10:29 AM

When tried from a machine with Outlook Express, the client pops up a message "timeout from server sending mail". Outlook 2k2 isn't returning me that message, but that's basically what's happening. Like I said, only to Hotmail.com. So I'm speculating the responses from hotmail are taking too long for my sendmail. How do I get this communication between my sendmail and hotmail to not timeout so fast?

Crued · 06-07-2002, 12:55 PM

It's fixed!!!

I don't know what differs from hotmail.com vs other servers but I had outbound TCP traffic on port 53 (DNS) blocked. I allowed UPD traffic on port 53 however. Simply added a rule in router to allow outbound TCP port 53, and everything works.

It's fixed, thanks for all your suggestions.

-Eric