Sending mail from behind firewall

[Cyrus Patel <cyrus.patel@efi.com>]

Hello,

I am behind a firewall here at work and using Exim as my MTA. Most of
the time (like 95%), I can send messages fine and they get delivered OK.

However, the other 5% of the time Exim gives me the error message:

This message was created automatically by mail delivery software (Exim).                                        

A message that you sent could not be delivered to one or more of its                                            
recipients. This is a permanent error. The following address(es) failed:

    rohanhet@au1.ibm.com                                                                                          
	SMTP error from remote mailer after MAIL FROM:<cyrus@10.61.1.122> SIZE=4319:                                
        host ausmtp02.au.ibm.com [202.135.136.105]: 501
	<cyrus@10.61.1.122>... Sender domain must exist

I understand the STMP server at the other end is trying to auth my IP
address which doesn't exist since it is masqueraded - but is there a way
around this? I think it has something to do with finding an external
server to relay my mail but I'm not really sure how it works - can
someone clear this up for me if possible. Any help would be really
appreciated.

Thanks,

Cyrus

-- 
Cyrus Patel - cyrus.patel@efi.com                                          
Software Engineer                  	                  Debian GNU/Linux 
Electronics for Imaging (EFI)                             (Woody)
Sydney, Australia.                                        ICQ: 50738541 
http://www.cyrusp.com  Mobile: +61 0402 266 731 cyrusmobile@linuxfreak.com