you can easly check if the SMTP port 25 is blocked.
Code:
Start > RUN > telnet mail.bbc.co.uk 25
You should see something like:
Code:
220 gateg.kw.bbc.co.uk ESMTP Sendmail 8.11.2/8.11.2; Sat, 18 Feb 2006 12:03:34 GMT
If you see it then the port is open, if not then its closed.
If its open you could try finding out the ISP that you are with.
Goto
www.dnstools.com, it should show your company ip address, click on it and it will give you a Whois output on who owns the IP address and what ISP its connected to.
With that info you may be able to find out what you ISPs SMTP server is.
Usaly they are things like:
Code:
mail.ISP.com
smtp.ISP.com
mailhost.ISP.com