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-   -   Firewall block emails (http://www.howtoforge.com/forums/showthread.php?t=9633)

Mathias 7th January 2007 19:58

Firewall block emails
 
Hi

I got a Debian server installed with The Perfect Setup - Debian but I can't connect to my MailServer on it .

When I telnet it I get this informations:

Klippinge-IT:~# telnet 83.95.198.14 110

Klippinge-IT:~# telnet 83.95.198.14 110
Trying 83.95.198.14...
Connected to 83.95.198.14.
Escape character is '^]'.
+OK Hello there.
quit
+OK Better luck next time.
Connection closed by foreign host.
Klippinge-IT:~#

IPTables says:
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
Edit/Delete Message


How does I get my desktop firewall disables or get it to allow my emails?

Best Regards
Mathias

martinfst 7th January 2007 20:08

Although you seem not to have setup a firewall, a test from my site gives:
Quote:

~$ telnet 83.95.198.14 110
Trying 83.95.198.14...
telnet: Unable to connect to remote host: Connection refused
Connection refused is normally a sign of a firewall somewhere between the internet and your server. If you logon to your server, can you do the telnet locally?

Mathias 7th January 2007 20:27

Quote:

Originally Posted by martinfst
Although you seem not to have setup a firewall, a test from my site gives:
Connection refused is normally a sign of a firewall somewhere between the internet and your server. If you logon to your server, can you do the telnet locally?

I have just looked on the server, my mistake it have changed IP to: 87.52.126.13 :)

martinfst 7th January 2007 20:47

A quick test gives an expected result.
Code:

~$ telnet 87.52.126.13 110
Trying 87.52.126.13...
Connected to 87.52.126.13.
Escape character is '^]'.
+OK Hello there.
user test
+OK Password required.
password hello
-ERR Invalid command.
user test
+OK Password required.
pass hallo
-ERR Login failed.

All the + and - responses are from your server and you should probably see in your logfiles me testing. You can do more tests yourself by using a valid user name on your system and follow a procedure like:
Code:

Type: user "username"
Type: pass "password"
Type: list
You will then get a list over the mails in your mailbox
Type: retr "mailnumber"
You will then see the mail with the mail number
End the session by typing "Quit"

Mind you, that you have a little amount of time before the POP3 server gives up (around 5 seconds, so be prepared and type quickly)

Mathias 7th January 2007 20:56

Quote:

Originally Posted by martinfst
A quick test gives an expected result.
Code:

~$ telnet 87.52.126.13 110
Trying 87.52.126.13...
Connected to 87.52.126.13.
Escape character is '^]'.
+OK Hello there.
user test
+OK Password required.
password hello
-ERR Invalid command.
user test
+OK Password required.
pass hallo
-ERR Login failed.

All the + and - responses are from your server and you should probably see in your logfiles me testing. You can do more tests yourself by using a valid user name on your system and follow a procedure like:
Code:

Type: user "username"
Type: pass "password"
Type: list
You will then get a list over the mails in your mailbox
Type: retr "mailnumber"
You will then see the mail with the mail number
End the session by typing "Quit"

Mind you, that you have a little amount of time before the POP3 server gives up (around 5 seconds, so be prepared and type quickly)

Dear Martin

It dosen't solve my problem with my firewall or something like that.

Best Regards
Mathias

martinfst 7th January 2007 21:02

Quote:

Originally Posted by Mathias
It dosen't solve my problem with my firewall or something like that.

Oke, but it's no firewall problem on your server. That one is fine. So you should look at your client or router to check what blocks your traffic.

Mathias 7th January 2007 23:06

Quote:

Originally Posted by martinfst
Oke, but it's no firewall problem on your server. That one is fine. So you should look at your client or router to check what blocks your traffic.

Hi .

What client?

And my server is directly connected to the internet

martinfst 8th January 2007 09:24

Quote:

What client?
Well, the mail client you're using to retrieve mails. Example programs are Oulook, Thunderbird, Eudora to name a few. I assume you're running that on your personal PC. There's no reason to run a POP3 client on your server. POP3 is to retrieve email. If you want to access mail locally on your server, you should use a mail client/tool like 'Mutt'.
Quote:

And my server is directly connected to the internet
Yes, as I noticed during my testing. That's oke.

Mathias 8th January 2007 15:08

Quote:

Originally Posted by martinfst
Well, the mail client you're using to retrieve mails. Example programs are Oulook, Thunderbird, Eudora to name a few. I assume you're running that on your personal PC. There's no reason to run a POP3 client on your server. POP3 is to retrieve email. If you want to access mail locally on your server, you should use a mail client/tool like 'Mutt'.Yes, as I noticed during my testing. That's oke.

About client ...

Is Postfix then my client ?

And how do I set it up so it works ?

martinfst 8th January 2007 15:45

Quote:

Is Postfix then my client ?
No, Postfix it the Mail Transport Agent, the glue between servers to transport mail. I assume you use a setup like:

Personal PC --> network --> Server

On your server, you run programs like Postfix (to transport mail) and POP3 (to connect the client and the server to retrieve mail). As a substitute for POP3 you can use IMAP. Both serve the same objective, though they use different protocols. For Postfix there are also a couple of other MTA's regularly used, like sendmail. On your PC client( often a windows PC, but other flavors become more and more popular), you use a mail client like Outlook, Outlook Express or Thunderbird to name a few.

To sent mail you use the server directly over the so called SMTP protocol. Thus your Personal PC client software (Outlook, etc) connects over the network with the SMTP protocol to the MTA (Postfix) on the server.

So it's POP3/IMAP to retrieve mail, SMTP to send mail. For POP3/IMAP often a package is used from a team of developers under the name Courier, but there a lots of other options. Perhaps the overwhelming amount of options is a bit scary, but try to read as much as you can. Running a mail server is do-able, but will require a significant learning curve. Try google for more information on setting up a mailserver, mail client usage or similar. I'm pretty sure useful information will popup.


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