OOT: Mail rejected with bogus helo

Scott Silva ssilva at sgvwater.com
Wed Apr 16 17:11:11 IST 2008

on 4-16-2008 7:48 AM Matt Kettler spake the following:
> Budi Febrianto wrote:
>> Dear All,
>> I know this OOT, but because many sendmail experts in here, I give it 
>> a shot.
>> I'm using sendmail-8.13.8-2.el5 with MailScanner 4.65.3.
>> Whenever my users sent emails to certain domains, it will rejected 
>> with this error.
>>  >>>>>
>> 553 yyy.yyy.yyy.yyy rejected due to spam, contact 555-505-5555 (bogus 
>> helo xxx.xxx.xxx.xxx)
>>  >>>>>
>> I'm not sure what happen, because I don't have the same problem with 
>> others domain.
> Your system is issuing a HELO in IP format, which is RFC compliant, but 
> some view this as a sign a system isn't properly configured and will 
> refuse mail from such systems.
> However, more troublesome is your system is issuing a HELO in IP format 
> using a private-range non-routable IP, This is blatantly 
> bogus when communicating with hosts outside your network, as those hosts 
> will never be able to route to and reach your server. (The 
> original intent, although outdated, is for the HELO to be usable as a 
> hint for where to return mail to if DNS fails to generate a MX or 
> implicit MX record. Generating private IPs here is clearly contrary to 
> that.)

To expand on this, just in case the OP is still confused, your private IP helo 
is possibly due to running your server natted behind a router. You will have 
to modify your servers configuration to give a FQDN or IP that is its natted 

> Ultimately, it's up to the administrator of the system you're trying to 
> contact to tell you why he's filtering you. Those are purely guesses on 
> my part, based on looking at the HELO's your server issued, and general 
> knowledge of what some admins do for filtering that not everyone does.

MailScanner is like deodorant...
You hope everybody uses it, and
you notice quickly if they don't!!!!

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