Dialup users cant send email

Ok this is off topic but something that has been plaquing my server network.

So I am betting on someone here having this experience - and possibly a solution.

Dialup users on my servers cannot send email using their mail.theirdomain.com. (they can recieve)
If they change to broadband it works fine.

My first thought was the ISP’s are blocking port 25 - so I contacted them personally and they are not blocking port 25. ALL of my dialup users cannot send mail - all different isp’s etc.

I have tested with local isp and sure enough i could not send email after downloading.

Only about 5% of my customer base - but still cant ignore any customers I prefer to take care of them all.

Anyone have any idea what I need to look for or what to check to see what might be the problem?

I’ve increased the timeout time of SMTP - thinking that due to dialup, its a slower connect process.


I’d say if you’re positive that it’s not the port 25 issue then the timeouts would be the next logical step John. I’d say it’s one of those 2 issues.


Yeah i have beefed up the time outs - gotta be something else.

They used to work. Now this isnt a problem with just one of my servers - its a problem with all of them so Im thinking its something to do with the datacenter network.

This probably isn’t it, but a lot of dial up IPs are blocked by different servers and those block list. Maybe the qmail relay setup is blocking the IPs of these clients and they aren’t allowed to relay? Maybe if you make them authenticate first before SMTP? What error do you get from you SMTP server?