If you mean the ISP you are going through might block port 25, then Tsohost have port 26 available. Most of my "client accounts" are set to that, as I used to be with O2 who blocked 25.
My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost
. Connection - Plusnet
Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.
"Where talent is a dwarf, self-esteem is a giant."
- Jean-Antoine Petit-Senn.
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.