I build a qmail server under a ADSL broadband following the instruction in "Life with qmail".

I don't have a fix IP, so I use a no-ip host name so the server is "cleverchild.no-ip.org" and I create an account "test@cleverchild.no-ip.org".
I can receive mail from all the world and I can send mail to myself (test@cleverchild.no-ip.org send to test@cleverchild.no-ip.org)
but when I send mail to other host (e.g. hotmail.com, yahoo.com)using "cleverchild.no-ip.org", the mail stay in the queue forever and the log said "deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/"

I read the some post here and found somebody said most ISP have blocked the port 25.(do I correct?)
What should I do to make my qmail server able to send mail to other host?

Thank you very much for your support

Hmm, is it common for ISPs to block outgoing SMTP? Mine doesn't.

You can make a quick check with telnet to see if sending to port 25 is blocked. First, find a mailserver: if you want to test against hotmail,

$ host -t mx hotmail.com

This gives a list of hotmail's servers for incoming SMTP. Pick any one... type this, don't forget 25 on the end:

$ telnet mx2.hotmail.com 25

I get the following (not blocked):

Trying 65.54.254.145...
Connected to mx2.hotmail.com.
220 mc2-f33.law16.hotmail.com Microsoft ESMTP MAIL Service,
.. etc etc

Then type quit, enter to exit.

If it just times out, or says something like "unreachable", try another mailserver or two... if they are all unreachable, odds are you have been firewalled somewhere.

If you are blocked, one solution would be to make qmail send everything outgoing via your ISP's mailserver. Look at smtproute in "man qmailremote".

Thank you soob,

I have tried telnet-ing a few mail servers and all got time out, except my ISP's mail server. I think I got blocked.

I will take a look about smtproute, Thank you very much soob