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My wired internet connection at work blocks the IMAP, POP and SMTP ports (the mail server is Exchange) which prevents me from using an email program like ThunderBird.

With the internet cable plugged in I can only use ThunderBird to read my work e-mail -- gmail is blocked by the firewall.

The guest wireless connection at work has the mail ports open. I thought this answer to link the gmail server address specifically to my wireless connection had solved my problem: with the network cable disconnected, I could read and write gmail.

But there are still two problems:

  1. With only wireless, authentication fails for my work Exchange server -- so I need my firewalled work connection for that
  2. As soon as I connect the network cable, the Exchange server works but then gmail fails because that also goes via the wired -and firewalled- connection.

I thought the answer above would solve this by routing traffic for gmail via the wireless gateway and Exchange traffic via the default (wired) gateway. But that's not the case when I plug in the cable.

My guess is that ThunderBird overrides this setting? Is it possible to assign a connection to an e-mail account or server address in another way?

Community
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alle_meije
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  • Why not use the web client of gmail? Then you are not storing your personal emails on a work PC. – Burgi Nov 19 '15 at 15:40
  • That's what I'm doing now, using Web mail for both accounts (I had already come that far). I would much prefer 1 separate, dedicated mail program for my e-mail accounts though. – alle_meije Nov 19 '15 at 15:46
  • "My wired internet connection at work blocks the IMAP, POP and SMTP ports ". You need to ask your IT department to allow exceptions to this. Maybe they don't want you to use unauthorised email programs at work? – DavidPostill Nov 19 '15 at 15:51
  • Note: Issues specific to corporate IT support and networks are off topic, see [What topics can I ask about here?](http://superuser.com/help/on-topic). – DavidPostill Nov 19 '15 at 15:52
  • @DavidPostill asked already and for the wired connection they won't change it. However they do provide an open wireless connection that I can use (but only by unplugging the cable or so it seems). My *technical* question is: is it possible to use the two connections side by side in 1 program? – alle_meije Nov 19 '15 at 15:57
  • This answer says it's not possible [ http://superuser.com/questions/224783/how-to-take-advantage-of-two-internet-connections-wifi-wired/340520#340520 ] ... although another answer to that questions also suggests the route command. – alle_meije Nov 19 '15 at 16:40

1 Answers1

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Playing with routing tables, as in the other answer, would seem to be the right solution to this, I think. However, just doing a 'ping' to a google imap server and then rerouting only that one through the wireless may be a little bit optimistic; I sincerely doubt that google has only one IMAP server.

Instead, I would suggest you modify your routing table in the following way:

  • Make sure there is no default route to the wired network, but remember what the IP address of the default router on that wired network is.
  • Add routes for all RFC1918 networks (10.0.0.0/8, 172.16/12, 192.168/16) to your routing table, with the IP address of the default router on that wired network. If the IP address on your wireless network uses an RFC1918 network too, however, make an exception for that.
  • Keep the default route on the wireless network.

This way, everything for "the Internet" will go over the wireless interface, and everything for your local LAN (including the local mail server) will go over the wired interface.

Wouter Verhelst
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  • Thanks @Wouter -- so it is the right way to do it, just more complicated. What I would prefer though is that if there is a wired connection to use the wireless *only* for mail. I can browse and SSH much faster using the cable. Or is that much more difficult to set up (*e.g.*, because w7 uses the wired connection by default) ? I know very little about RFC1918 and routing tables. – alle_meije Nov 20 '15 at 08:25
  • It is indeed way more complicated to set up. The only way I can think of is to use some sort of application proxy that has specialized knowledge of your routing table. Don't even know if that exists for windows, let alone how to set it up... – Wouter Verhelst Nov 23 '15 at 10:44
  • Then your 1st solution is worth a try. I will see how far I get before calling for help again :). Its not actually that bad because large files inside my LAN will still go via the wired interface IIUC? Only a problem for transferring big data with the world outside.. – alle_meije Nov 23 '15 at 10:50
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    Correct, only for data outside your local network. – Wouter Verhelst Nov 23 '15 at 10:51
  • The next day it worked! (re-boot alone was not enough?) This is great! For the wireless I do need to login via the browser (that cannot be automated) but it's worth it for being able to use a normal e-mail program. One more question though if I may: would something like Citrix Receiver also require a separate rule in the routing list? – alle_meije Dec 03 '15 at 10:06