LinuxQuestions.org
Visit Jeremy's Blog.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices


Reply
  Search this Thread
Old 06-07-2004, 10:56 PM   #1
redss
Member
 
Registered: Jun 2003
Posts: 168

Rep: Reputation: 16
ip tunneling question


My company firewall has port 110 blocked to prevent us from checking POP3 email.

I am however able to connect to my linux box at home through ssh.

Can I enable port forwarding to enable my pop3 client to send pop requests tunnelled through SSH (maybe using putty ssh client, or some other way) to connect to something on my home unix box which will remap the pop3 requests to port 110, to reach my pop3 email server out on the internet?
 
Old 06-08-2004, 10:50 AM   #2
linuxxed
Member
 
Registered: Feb 2004
Posts: 273

Rep: Reputation: 30
I take it you can connect to any port from your company to your home other than 110??

If yes the you can use ssh remote forwarding i.e ssh to listen on company localhost to use a port on your home machine to connect to your hostingprovider:110.

Connect your company outlook to localhost: [whateverport you choose]

There are so many tutorials on the web on how to do this.
 
Old 06-08-2004, 05:02 PM   #3
Weaver
LQ Newbie
 
Registered: May 2004
Distribution: Slackware, Debian
Posts: 4

Rep: Reputation: 0
Yes, this is entirely possible and quite easy to boot. However, you may want to think about sending your password plaintext across the Internet. It is one thing to POP from the ISP you receive service from, your traffic in this case generally never leaves the ISP's network (although may use local lines to arrive at the ISP). However, POPing across the Internet is a totally different scenario. Now, your plaintext password is travelling across the public Internet.

SSHing into your Linux box at home will create a secure tunnel between you and home, but then the secure tunnel stops there. The linux box (specifically the ssh daemon) then forwards the traffic in its "original" form the the destination host specified. The POP3 session is only encrypted from you to your linux box.

You said you were using PuTTY, so I can show you how to set that up specifically.

Assumptions:

Your linux box: mybox.dyndns.org
The POP3 server you are trying to get to: pop.acme.org

Replace the appropriate hostnames or IP's when you set it up.

Setup your PuTTY session as normal. In addition, PuTTY contains an "Auth" page. It is near the bottom of the left hand window.

In the "Source Port" field (near bottom of now right hand window) you will put '110' (without quotes).

In "Destination" field you will put 'pop.acme.org:110' (without quotes)

Make sure the 'dot' is in the "Local" field since this will be a local tunnel.

Go ahead and click "Add." When you connect to your linux box at home (mybox.dyndns.org) the tunnel will be enabled. Now on your machine at work, you can setup your POP3 server to 127.0.0.1 .

When your mail client at works connects to 127.0.0.1 on port 110, the traffic will be tunnelled (encrypted) to your linux box at home. It will then go out to pop.acme.org:110 via conventional (non tunnelled) means.

Keep in mind these specific instructions are for PuTTY. Command-line 'ssh' would be something like 'ssh -L 110:pop.acme.org:110 login@mybox.dyndns.org'

If you have questions, ask.

-Weaver
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
SSH Tunneling Question anon111 Linux - Networking 9 02-07-2006 08:04 PM
Tunneling Randvegeta Linux - Networking 4 09-21-2005 10:42 AM
Not your average SSH tunneling question gauge73 Linux - Networking 5 05-02-2005 10:23 PM
incoming tunneling or tunneling via a 3rd party? JustinHoMi Linux - Networking 1 04-15-2005 01:57 PM
ssh port forwarding (tunneling?) question podollb Linux - Software 4 10-20-2004 01:12 AM

LinuxQuestions.org > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 06:34 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration