Can a firewall block outlook from checking mail or is it my mailserver that is down?

Any firewall could block the ports that any mail transfer protocol uses. SMTP uses port 25, POP2/port 109, POP3/port 110, and IMAP/port 143, for example. If you are blocking any of those ports, you could be blocking your email server. ISP's can also block mail transfer ports unless being used by their mail servers.

What type of firewall are you using?

Is this mail server part of your office or home equipment?

Has it worked ever before, or is it in the process of being set-up?

Answers to these questions would really help.

it's for at home
i use outlook xp (worked perfectly)
i installed black ice defender
then couldn't check mails anymore
but i really like to have a firewall....
i'll try to open the ports you mentioned.
i'll keep you informed wether it works or not

BID to my knowledge doesn't block outgoing ports, only incoming. I'm wondering if its something else perhaps?

I know everybody has their personal preference when it comes to software firewalls. I have never used BID so I cannot personally comment on the product.

I have used Zone Alarm almost since its conception. It is free and would recommend it to anyone. It will ask you about any program that wants to access the Internet. This includes your email program. You have the option to let the program access just this once, all the time or never.

Ok, so you must allow your email client to access the well known ports for pop3 and smtp.

I know Zone Alarm is program oriented, and I would assume that the newest BlackIce is too. If a program wants to access the internet, you just give it permission to do so. Once given permission, it should be able to do whatever it needs without being blocked. There are more advanced settings that can be enabled to specifically allow or block certain ports with ZA Plus and Pro for each individual program or globally. Not sure about the latest free version of ZA or BlackIce PC Defender. I have just never used them.

i've set open the ports mentioned here and now it works again.

No, you are probably doing the right thing with Blackice. Zone Alarm is what I was referring to.

Owkay...
Thx for helping

I'm not sure how your firewall works. If there is a way to only allow Outlook XP to use the ports, that is the way to go. You really don't want to just leave a port open for anything to use. You may have already done the right thing, as I'm not familiar with Blackice PC Defender.

I use Zone Alarm 3.0 and I leave all apps that connect to the LAN or Internet with a question mark, with the exception of Symantec's Live Update™ & Norton AntiVirus Agent (which is with NAV 2002. It is the app that scans incoming & outgoing e mail for viruses/worms.)
When I want an app to connect to the Internet, e.g. Internet Explorer, Outlook Express, Messenger, etc. A popup screen comes up asking me if I want to let whatever app I choose access the Internet. I click yes. It only takes a couple of seconds to press yes or no and I like the extra security. IMHO Zone Alarm is the tops in firewall software.

Yes I concur.. ZAP is a great app for home use, or even desktop business use.