New DSL lines cannot retrieve mail from one mailserver

[bennetje]

Hi, we just switched from T1 to two DSL lines. With IE we
cannot access an externe exchange server by using OWA.
(

https://mail.server.com/exchange

IE gives pages not found error. Some of my users have a mail account there.
If we use the T1 connection there is no problem.
I called SBC (the new DSL provider) and asked if they use
a blackout list, but there answer is no, they block nothing. Someone here has a SBC account at home and works fine from his home.
A call to the mail account ISP they told me that
they have no idea what that can be.
A ping failed from both T1 and DSL, they might have ping
blocked at the firewall.
Has someone any idea what this can be.
Thanks so far,
/Ben

 

[bustamove]

try


telnet mail.server.com 443 to see if the port is open for you. if OK, make sure you are not behind a proxy for this new ISP

 

[bennetje]

Thanks so far, yes that is a simple test.
If we use the T1 link telnet works fine.
If we use the new DSL line telnet failed.
What does this tells me? Do they block us?
I asked them already if they can check there firewall
log to see if we were denied. No answer yet. Is that the right approach?
Any usefull information how to proceed is welcome.

/Ben