Topic: Mail Proxy - Outlook Express

[Richard Bruce]

Hi,
I've got a minor problem in setting up e-mail. We have an internally routered network. For security reasons (and convenience) I require users to use port 3128 on our e-smith box as a proxy server. This works fine for all web requests (also allows me to authenticate all web users) BUT...some users require to send e-mail via an external ISP's SMTP connection. This particular ISP allows us to do this, and it works fine for anyone that is allowed to connect directly to the internet using e-smith's transproxy facilities.

If however the user is on a network that is not local to the e-smith box they cannot send mail via the external ISP. Outlook Express (for Macintosh) supports the use of an external mail proxy, is there any way of getting our e-smith 4.1.2 box to support this? Does it already do this but use a port different from 3128? What I want the server to do is to pass SMTP to the internet via a proxy port setting. I'm not interested in SMTP relaying.

I hope the above makes sense and someone out there can help.

Richard Bruce

[Richard Bruce]

I've also had another thought about this. I will also need to be able to proxy POP3 requests as well! Outlook Express must redirect all SMTP and POP3 requests to the mail proxy port defined in the preferences. Again does anyone know of a way for e-smith to emulate this behaviour?

Richard

[Richard Bruce]

I've also had another thought about this. I will also need to be able to proxy POP3 requests as well! Outlook Express must redirect all SMTP and POP3 requests to the mail proxy port defined in the preferences. Again does anyone know of a way for e-smith to emulate this behaviour?

Richard

[Les Mikesell]

It should be possible to find and install application-level proxies for smtp and pop, but do you really want to just treat your whole network the same as the directly attached part and NAT outbound connections for them?   This should be a matter of setting the server as the default route known to your routers (assuming it is the only way to the internet)  and adding the other subnets with the 'local networks'  admin link, which you must have already done.

[Richard Bruce]

Les,

That's actually what we did! My only "concern" with this is that I have had to use the absolute ip address, so if that particular ISP changes the address of their mail server we'll have to update manually. As a point of interest if anyone else tries this and wants a tip we utilised our "gateway of last resort" to achieve this. In our network all "last resort" requests are directed to a particular router, so rather than updating every single router with the static route we only updated the last resort router. A side effect of this was that we then had to permit that router access via the firewall as the origination address became our last resort router instead of the actual originating network. No doubt there is a perfectly logical explanation for this and if I get time to look in to it I'll update the post, but nothing springs immediately to mind and I'm too busy at the moment!

Thanks for taking the time to reply.

[Les Mikesell]

I think it would solve your address problem if you used the smeserver as the dns server for the other networks too, or at least configured whatever local servers you have there to use the smeserver as a forwarder for queries.   The first way you would make all your local entries on the smeserver, the second you would keep local entries where they are but you would still be able to resolve outside addresses.