Connection refused in mail server

[Krudtugle]

I use fetchmail to collect mail from an external mail account to my B3. It works fine to read the mail with the Horde webmail client, but when trying to use an email client (Thunderbird in my case) it doesn't work.

Thunderbird reports "The connection was refused". My setup is:

1. My easyfind name configured as mail server in Thunderbird.
2. Connection security: SSL/TLS, Port 993.
3. The firewall in my ADSL modem is turned off.
4. IMAP server is enabled in the firewall in B3.

I don't know how to find the problem. Anyone knows where the logs related to mail are stored in B3?

Thanks!

[Cheeseboy]

Hi,

You'll find the log files (called mail.*) in /var/log.

This is what I would do first:
- Make sure dovecot listening on port 993 on the B3

Code: Select all

# netstat -anp | grep 993
tcp        0      0 0.0.0.0:993             0.0.0.0:*               LISTEN      2849/dovecot

- Eliminate any name resolving issues by using the IP address in your Thunderbird settings rather than the easyfind name

/Cheeseboy

[Krudtugle]

OK, thanks.

I got the following result when running netstat:

Code: Select all

root@b3:/# netstat -anp | grep 993
tcp        0      0 0.0.0.0:49152           0.0.0.0:*               LISTEN      1993/mediatomb  
tcp        0      0 0.0.0.0:993             0.0.0.0:*               LISTEN      1962/dovecot    
udp        0      0 127.0.0.1:42032         0.0.0.0:*                           1993/mediatomb  
udp        0      0 0.0.0.0:1900            0.0.0.0:*                           1993/mediatomb  
unix  3      [ ]         STREAM     CONNECTED     5485     1993/mediatomb   

I can't really interpret the result. Is Dovecot listening on port 993?

What is Dovecot, btw? Is it the mail server?

I also looked in the logs. In mail.warn, I found the following:

Code: Select all

Nov 13 09:09:56 b3 dovecot: dovecot: Killed with signal 15 (by pid=23717 uid=0 code=kill)

In mail.log och mail.info (which seemed pretty similar in content, I found a number of these:

Code: Select all

Nov  9 22:17:05 b3 dovecot: imap-login: Login: user=<robban>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Nov  9 22:17:06 b3 dovecot: IMAP(robban): Disconnected: Logged out bytes=103/524

It seems that I get logged out immediately after being logged in.

Anyone can see anything in these log lines looking strange?

[Cheeseboy]

Hi again,

I can't really interpret the result. Is Dovecot listening on port 993?
What is Dovecot, btw? Is it the mail server?

Yes, it is listening on port 993 and accepting requests from all network interfaces.
Dovecot is the process that handles the incoming IMAP requests. I.e. the server you connect to to read your email.

It seems that I get logged out immediately after being logged in.
Anyone can see anything in these log lines looking strange?

No, all looks normal.
The message about dovecot being killed is normal if the process is being shut down (like when you are rebooting B3).

The messages showing a login and then quickly a disconnect also shows the IP address of the client connecting to dovecot: 127.0.0.1. This means it comes from a process running on B3 itself, probably the webmail client checking for new mail (unless you are using SSH tunneling).

So, no trace of your attempt to access your email on the server side.
Probably a network issue.

Try accessing your email in Thunderbird from your home network by just using b3 (or 192.168.10.1) as IMAP server name in your Thunderbird settings. This will confirm that you can access the IMAP server with your client settings.

When that is working, try from the outside using your public IP address.
This is most likely where it fails, and there could be any number of reasons to why it fails.
As an example I could not get it to work when accessing it from work, even though it worked from a friend's network. It turned out my workplace blocks outgoing traffic on port 993 (in fact all ports except 80 and 22)...

[Krudtugle]

Yes, you're right!

To start with, thanks a lot for the detailed reply!

I CAN access it from the local network by using 192.168.10.1 as IMAP server in Thunderbird.

But when trying to reach it from my mobile phone with my (current) external IP address, I get "connection timed out".

At least, I don't get "connection refused"

BUT, it's kind of strange. Why wouldn't I be able to connect from the outside? My mobile phone isn't on a network blocking any traffic and my firewall in the ADSL modem is turned off...

[Cheeseboy]

OK, so now it is a network configuration issue.
I saw this thread http://forum.excito.net/viewtopic.php?t=2585, and frankly it left me confused with regards to your network setup.
You have to decide how you want to use the B3, and then configure it and your ADSL box accordingly.

Your Thomson ADSL unit is most certainly also a switch, a firewall, a router, a DHCP server and also forwards DNS requests from the local network to the internet (assumption here, I don't know anything about it).
B3 is also capable of doing all of these things, so you need to decide which device you want to use for each thing.

When you have problems, please let us know exactly how all these things are set up (or we will be guessing, as I am now).

I guess you are unable to access your B3 from outside because you have not configured that Thomson device to forward incoming requests to the B3 on the local network.

Cheers,

Cheeseboy

[Krudtugle]

Now we're talking!

First, let's start with my network configuration. As you mentioned I plan to use the B3 as (wireless) router, firewall, DHCP server (and DNS forwarder).

So, I want my ADSL modem to forward all traffic to B3. To start with, I've turned off the firewall in the modem, but now I run into trouble. There's no port mapping table in the modem, so I'm not able to forward the traffic to B3 port by port.

The only thing I can do is to assign games and programs to network units from a predefined list:

AIM Talk
BearShare
BitTorrent
Checkpoint FW1 VPN
Counter Strike
DirectX 7
DirectX 8
DirectX 9
eMule
FTP Server
Gamespy Arcade
HTTP Server
HTTPS Server
iMesh
KaZaA
Mail Server (SMTP)
Microsoft Remote Desktop
MSN Game Zone
MSN Game Zone (DX)
NNTP Server
PPTP Server
Secure Shell Server
Steam Games
Telnet Server
VNC
Xbox Live

Of these, I've assigned FTP, HTTP, HTTPS and Mail (SMTP) Server to the B3. But there isn't even IMAP server in the list!

Additionally, there IS a page in the modem config GUI called "Tilldela en anslutnings allmänna IP-adress till en LAN-enhet". Which is exactly what I want to do. I want to assign all network traffic to the network unit B3. BUT it just say "Igen kompatibel anslutning hittades.".

So... you're right! The problem is obviously that the ADSL modem isn't forwarding the traffic, BUT on the other hand it doesn't seem possible to configure it to do so.

Maybe time to get another modem?

A big thanks for taking the time to help out!

[Cheeseboy]

Maybe time to get another modem?

Sounds like it, and perhaps for more than that reason:

I've downloaded and tested this app on my phone:
http://apps.androidtapp.com/#penetrate/ ... .penetrate
Using this, I have successfully gained access to Thomson wireless access points in my neighbourhood (research purposes only). They really seem to welcome intruders, with a nice web interface telling me what username to use, listing all the hosts on the internal network, and a telnet interface with options to clear the logs to hide the tracks of my illegal presence...

So at least change the default security settings.

[Krudtugle]

That really sounds astonishing!

I'll not buy another Thomson modem then...