Failure of smtp on port 25

[Bob_PHP_Builder]

i have setup smtp on 2003 web edition, IIS. Port 25 is blocked and will not respond to any telnet open commands, so i have opened port 26 which now works fine... IS this any less secure than port 25?

Thanks

[MarkR]

Do you mean from localhost, or externally?
Do you have any third party software firewall applications installed (Or AV which might interfere)?
Has your network admin instigated any block on port 25 without documenting it?
Has your ISP blocked port 25 themselves?
Does the client you're testing have any outgoing block on traffic to port 25?

Do you know how far the messages get down the route you're trying?
Have you tried any other routes (e.g. LAN, localhost, via another network or provider)?

Mark