Problem with Postfix and SMTP port 25

I followed the "Perfect Hardy Heron Ubuntu Server" step by step, but I am still unable to access my remote SMTP server from my desktop (i.e., I cannot send a test email using Thunderbird.)

The server resides on a VPS host, and I can send mail from the command line. However, I cannot connect to the SMTP server via Thunderbird, not can I telnet to port 25.

How do I:

1. Test if port 25 is open?
2. Open it safely if it isn't?
3. Change the port if my local ISP is blocking it?

Thanks!

Kevin J

 

If your server has local ip address for example 192.168.1.1 you can command to another local computer:
telnet 192.168.1.1 25

it should show the smtp greeting.

If your ISP is blocking port 25, maybe you can consider using submission port.


cheer,
Joel

 

What's the output of

Code:

netstat -tap

? any errors in your mail log?

 

Netstat and logs

Here's the output of sudo netstat -tap
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 localhost:mysql *:* LISTEN 7856/mysqld
tcp 0 0 *:www *:* LISTEN 9585/apache2
tcp 0 0 <FQDN> *:* LISTEN 7318/named
tcp 0 0 localhost:domain *:* LISTEN 7318/named
tcp 0 0 *:smtp *:* LISTEN 11732/master
tcp 0 0 localhost:953 *:* LISTEN 7318/named
tcp 0 0 *:https *:* LISTEN 9585/apache2
tcp6 0 0 [::]:imaps [::]:* LISTEN 9181/couriertcpd
tcp6 0 0 [::]op3s [::]:* LISTEN 9088/couriertcpd
tcp6 0 0 [::]op3 [::]:* LISTEN 9023/couriertcpd
tcp6 0 0 [::]:imap2 [::]:* LISTEN 9124/couriertcpd
tcp6 0 0 [::]:ftp [::]:* LISTEN 11019/proftpd: (acc
tcp6 0 0 [::]:domain [::]:* LISTEN 7318/named
tcp6 0 0 [::]:ssh [::]:* LISTEN 3487/sshd
tcp6 0 0 [::]:smtp [::]:* LISTEN 11732/master
tcp6 0 0 ::1%##########:953 [::]:* LISTEN 7318/named
tcp6 0 1200 <FQDN>:ssh ip###############:54923 ESTABLISHED 21688/sshd: ## [

"mail.err" is empty, and "mail.log" loks fine. Saw something in "mail.info", though; what does this mean?

Feb 18 20:26:30 mail imapd: chdir Maildir: No such file or directory

BTW, many thanks, All, for your assistance!

Kevin J

 

Looks good.

Is there a firewall that is blocking port 25?

 

Firewall?

How do I tell?

(Thanks.)

Kevin J

 

What's the output of

Code:

iptables -L

?

 

IP Tables output

Here it is; I haven't set up any rules, yet, evidently:

Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

 

Is the server located in a data center, or is it hosted on a DSL line or something similar? In the latter case, make sure that your ISP doesn't block port 25.

 

It's a virtual server that I have complete control over, other than assigning the IP address.

I access the Internet via a high-speed connection through my cable company. At this point, I'm guessing they don't allow access to port 25 on any domain except their own.

How do I tweak my postfix settings to allow access on a differetn port, and what ports would be suggested?

Falko, thanks for your help; it is greatly appreciated.

Kevin J

 

You can use submission port. Just modify your master.cf.

Joel