Dial-up without SMTP Filter?

[Mel]

I've got a half dozen e-mail accounts configured in Outlook. They are on two of my own domains. I use the SMTP server (with authentication) that I host myself. When connected to Comcast cable or any number of my clients ISP's at their offices, I can send e-mail no problem.
I'm trying to find a dial-up provider for when I'm on the road and don't have high-speed access that allows you to send e-mail through an SMTP server other than their own!! As a result, everytime I need to use dial-up, I have to go re-configure my 6 e-mail accounts outbound server setting, when I get back to my office and plug into the lan, I have to change the outbound server address back. Its really tiresome.
I've tried Earthlink, NetZerom and AT&T Worldnet. All of them block outbound SMTP to any servers other than their own.
So while I want to eliminate the SMTP filtering, I don't want to have to go with some small outfit that will be bought out or out of business in a year.

[justin]

Many ISPs use more than one backbone provider. Some of their access numbers may have port 25 blocking and others may be open. If you travel a lot, studying which ISP uses what backbones in which city, could be a huge project. I agree with Boz, don't use port 25.