Hi this is Varun,

i am creating a mail server,
i have installed qpsmtpd and i am using it on port 25,
my smtp is working on port 26,
however i am getting an error when i send a test mail from "swaks"

# swaks -s 192.168.0.29 -p 25

To: abc@yahoo.com
=== Trying 192.168.x.xx:25...
=== Connected to 192.168.x.xx.
<- 220 server1.xyz.com ESMTP qpsmtpd 0.40 ready; send us your mail, but not your spam.
-> EHLO server1.xyz.com
<- 250-server1.xyz.com Hi Unknown [192.168.0.29]
<- 250-PIPELINING
<- 250 8BITMIME
-> MAIL FROM:<root@server1.xyz.com>
<- 250 <root@server1.xyz.com>, sender OK - how exciting to get mail from you!

-> From: root@server1.xyz.com
-> Subject: test Mon, 17 Aug 2009 14:51:21 +0550
-> X-Mailer: swaks v20061116.0 jetmore.org/john/code/#swaks
->
-> This is a test mailing
->
-> .
<** 451 Queuing declined or disabled; try again later
-> QUIT
<- 221 server1.xyz.com closing connection. Have a wonderful day.
=== Connection closed with remote host.

Please help!! with this :
451 Queuing declined or disabled; try again later

Thanks in advance!!

That message is coming from the remote server, did you try to Google for that error??? You should install DomainKeys to sign your emails from a specific domain. However, even once this is done, you will still get some 451 errors, especially from Yahoo accounts, which is what it seems you're trying to do, in your example.

In an attempt to block spammers, Yahoo is blocking an extremely high number of "good" emails. You get what you pay for...shift your email host to another provider, and see what happens.