Problem in Squirrelmail

Dear Forum:
Hi:
Hope to see you in good health.
I want to send and receive emails using my IP address and not my
domain name!, i.e. the email address should be of the format
name@[ip_add_ress].
I installed Squirrelmail, made an entry of it at apache Webserver,
i.e. when i wrote "http://localhost" in my browser ,i got the login
page of squirrelmail.
I made different accounts and hence can login in squirrelmail, using
different user names, like root, or httpd etc etc.
I manage to send emails, the email were of the format:
username@servername.
where:
username = my login name with which i login
servername = my server name which i choose for squirrelmail, u know
"./configure", I can even choose "hotmail.com" and can send emails,
but u know it is unethical :). I can send emails to any body around
the world. Anyway to cut the story short here is my Problem:
I can send emails but I cant receive emails, I know that I have to
send emails in the format name@[202.5.145.41], but when I send email I
got message that
"Couldnt send mail for Four Hours".

So I can summarize my problem as
"I can send emails, But iam unable to receive emails"
Here are my server settings( I think so these are enough:) ) of
Squirrelmail as follows:
squirrelmail version = 4.1.2
Redhat version = Redhat Linux 9
domain name = example.com( i even tried my IP address)
Invert time = False
sendmail or smtp = smtp
IMAP Settings:
IMAP Server = Localhost
IMAP Port = 143
Authentication Type = login
Secure IMAP(TLS) = false
Server Software = uw
Delimiter = Detect

SMTP Settings:
SMTP Server = localhost
SMTP Port = 25
POP Before SMTP = False
SMTP Authentication = none
Secure SMTP(TLS) = false

Also my webserver name is my IP Address( i.e. 202.5.145.41).
And my IP address is a registered IP address.
So Kindly help me and point out what is wrong, as far as i can guess I
think so my SMTP settings are all right because i can send emails, but
since I cant receive any email so I think so some thing is wrong with
my POP3 Settings,
Where i can rectify this, I am sort of new in this field, so kindly
treat me just like that.
Your help will be greatly appreciated.
Thank you in advance
Azhar Bilgrami

This is not my area so this is probably a long shot....
tried to change your IMAP-server to your IP(202.5.145.41)?

***Moved to Linux Applications***