Sending email without port 25

ajatiti · 03-11-2008, 10:04 AM

Hi,

I have a linux server (RHEL4). I have configured to mail the output of a script to my inbox (Outlook).
I configured sendmail that opens port 25 and it works fine.

Now, how can I make this possible without opening port 25?

The server is not in the domain it is in localhost.localdomain.

But the SMTP server that I am using is in another windows domain.

Could please someone help me in acheving this?
Appreciate all your help.

Thanks,
Aj

ajatiti · 03-13-2008, 04:48 PM

Is there any way to put the smtp server address in teh script itself so that I can send email without starting sendmail.

Else is this possible: Starting sendmail but not the port 25.
If I start sendmail "nmap -O locahost" command should not show port 25 listed.

Thanks!

billymayday · 03-13-2008, 05:10 PM

I don't know sendmail, but certainly in postfix you can over-ride the smtp port. I woudl assume you can in sendmail.

Have you looked into the mail command? I don't know if you can specify a port for that, but it doesn't need sendmail as far as I know.

ajatiti · 03-14-2008, 02:08 PM

Since the machine is a localhost and teh smtp server is in another domain. To give the smtp server address, I need to use sendmail ..right?

I dont understand why does it open a listening port while I want it only to send the mails.

Yeah..I am using Mail command in my script.
Mail -s "Subject" aj@anotherdomain.com

Thx
Aj

billymayday · 03-14-2008, 03:17 PM

Then I don't think you need sendmail running to use mail (try it)

frndrfoe · 03-14-2008, 09:20 PM

If you have a line like this in your /etc/mail/sendmail.mc file then sendmail will only accept mail from the localhost.

Code:

DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

You can shut down the port using the firewall.

ajatiti · 03-16-2008, 04:20 PM

Thanks for your replies,

I stopped sendmail and then tried sending mail. It doesn't.

Also when I use iptables to reject the dport 25 it doesnt send mails.
I am using this iptables command:
iptables -A INPUT -p tcp -m tcp --dport 25 -j REJECT

Is this the correct command?

Also I have added nameserver in the /etc/resolv.conf, still don't work.

Thanks,
Aj

livetoday · 03-17-2008, 06:30 AM

I think, Iptables will only reject the connection attempt made on port 25, but it won't close the port and port should be open even if you want only to send email. However, you may open the port on another inteface if you don't want it on localhost.

Quote:

Originally Posted by ajatiti

Thanks for your replies,

I stopped sendmail and then tried sending mail. It doesn't.

Also when I use iptables to reject the dport 25 it doesnt send mails.
I am using this iptables command:
iptables -A INPUT -p tcp -m tcp --dport 25 -j REJECT

Is this the correct command?

Also I have added nameserver in the /etc/resolv.conf, still don't work.

Thanks,
Aj

ajatiti · 03-19-2008, 05:25 PM

ok..Instead of using sendmail. If I update the DNS resolver will it work.
Will it be able to resolve my email id on another domain instead of specifying the SMTP address?