cannot send mail. Can receive ok.

[sul]

hi,

i'm using Fedora 9 and sendmail 8.14.2


I can receive emails and can only send mail locally to other users on
the same server, but I am unable to send mail externally. after 4
hours, I get a returned message which says: Warning: message still
undelivered after 4 hours. Will keep trying until message is 5 days
old....


I have tried to send to multiple external e-mail addresses with the
same results.

again, i CAN receive mails from anywhere (internal or external); just cannot send externally.

how do i pinpoint the problem and resolve?


thanks!

[steelaworkn]

This may seem elementary but seems like a firewall protocol for outgoing mail. Just as a firewall can block incoming stuff, it can also block outgoing stuff.

[sul]

Thank you for the suggestion. However, I did test by temporarily turning off the firewall and tested sending email externally. Still, the email does not want to go through. btw, i have also tried turning off selinux policy enforcement by using setenforce 0 command and still the same results.

if you have any other suggestions, please reply.

thanks!

[davecgs]

Fedora also has SELinux. That may be blocking it as well.

[sul]

Thanks for the suggestion. I actually disabled SELinux and firewall temporarily before sending and it did not help resolve.

If you have any additional suggestions please let me know.

Thanks!

[savage]

It could be your ISP blocking outbound port 25. This is quite common to "help" fight spam.

From a terminal try 'telnet smtp.googlemail.com 25', if you get the following then it's not your ISP:

[savage@hotrod ~]$ telnet smtp.googlemail.com 25
Trying 216.239.59.16...
Connected to smtp.googlemail.com.
Escape character is '^]'.
220 mx.google.com ESMTP somecrazycode

Check /var/log/maillog to see what's going wrong.

[marcrblevins]

You have any of these at the end of your /etc/mail/sendmail.mc?

MAILER(local)dnl
MAILER(smtp)dnl
MAILER(procmail)dnl

Think you need the last two lines.

[John the train]

Originally Posted by savage

It could be your ISP blocking outbound port 25. This is quite common to "help" fight spam.

My ISP blocked mail from my secondary address until I vaildated it - human action to prove I wasn't a bot I assume - but not a total block. Very strange.

[sul]

Thank you for the suggestion. indeed, i cannot telnet to port 25 to any IP outside my subnet. Is there an alternative way?

looking forward to your suggestion.

thanks!

[sul]

Originally Posted by marcrblevins

You have any of these at the end of your /etc/mail/sendmail.mc?

MAILER(local)dnl
MAILER(smtp)dnl
MAILER(procmail)dnl

Think you need the last two lines.

I have the following as part of /etc/mail/sendmail.mc:

MAILER(smtp)dnl
MAILER(procmail)dnl

I do not have: MAILER(local)dnl

looking forward to any suggestions...

thanks!

-s.

[savage]

There are services out there that offer alternate port SMTP, usually you have to pay for them, no-ip.com do a service, I think it's £25 a year there abouts.

I imagine DynDNS offer the same thing, shop about, you may be able to find a free service.

You'd need to get your local SMTP server to relay to the alternate port server, I've never done that so can't say how easy it is.

You could if you wanted just use the alternate port server (probably easiest).

[sul]

I read somewhere that I can use port 587 instead. Is this indeed an option in sendmail? I actually tested by doing:

telnet smtp.googlemail.com 587 and was able to get a response:

telnet smtp.googlemail.com 587
Trying 209.85.221.150...
Connected to smtp.googlemail.com.
Escape character is '^]'.
220 mx.google.com ESMTP 14sm1606693qyk.42

Any thoughts?

thanks!

[savage]

You could use that for Gmail yes, but not your own e-mail server.

The reason being, when your server tries to send an e-mail to say hotmail.com, it will always try and talk to hotmail.com on port 25, which your ISP is blocking.

If you used Gmail port 587 as you said, you'd be using Gmail's server, which would then connect to hotmail.com on port 25. Gmail's servers will only let you send from Gmail accounts though, so you'd need to register with them and use an @googlemail.com e-mail account.

Edit: Thats basically the same process as using a service like No-IPs alternate port, except they'll let you use your own e-mail address.

[sul]

Thank you for the great explanation, this really helps!

I will request our ISP to unblock port 25 for the server. Failing that, may need to resort to your earlier post on using a service.

Many thanks!!!

[Sauron]

Depending on your ISP you might need to buy a commercial connection to get unblocked service.