SMTP addresses in <>

Rich Kulawiec rsk at gsp.org
Fri Jan 4 16:37:04 UTC 2008


On Fri, Jan 04, 2008 at 07:51:15AM -0800, Seth Mattinen wrote:
> Our mail servers reject connections that don't follow the RFC. Am I wrong 
> to do this? 

Nope.  His software is either misconfigured or broken.

I'm aware of the be-liberal-in-what-you-accept philosophy (and followed
it for many years, still do in some cases), but no longer think it's
applicable to inbound SMTP.  The way I've put it is that the more
someone's SMTP sender looks like a spam source -- say, missing rDNS or
HELOing as something invalid or not sending valid SMTP commands -- the
more likely it is that someone's mail system will reject, defer or
quarantine the traffic.  So it's in everyone's interest to make sure
their outbound SMTP traffic is as compliant with de jure and de facto
requirements as they possibly can -- doubly so given that this is
quite often something as simple as fixing a HELO string or creating
a single PTR record or something similar.

---Rsk



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