[lug] Email brokenness?

[David Anselmi]

Chris wrote:
[...]
> <username at comcast.net>: host gateway-s.comcast.net[204.127.202.26] said: 550
>     [PERMFAIL] comcast.net requires valid sender domain
> 
> What the heck is that supposed to mean, and what do I do about it?

Well, you didn't say what IP you're coming from so I can't check your 
reverse DNS.  You didn't say what HELO, MAIL FROM, TO, or FROM you're 
using.  But the idea that your DNS is flaky sounds good to me.

This 550 is caused by an unresolvable domain in the MAIL FROM line (not 
the HELO):

$ telnet gateway-s.comcast.net 25
Trying 204.127.202.26...
Connected to gateway-s.comcast.net.
Escape character is '^]'.
220 sccrmxc12.comcast.net - Maillennium ESMTP/MULTIBOX sccrmxc12 #91
helo localhost
250 sccrmxc12.comcast.net
mail from: <me at localhost>
250 ok
rcpt to: <you at comcast.net>
550 [PERMFAIL] comcast.net requires valid sender domain

Currently your syntacticsugar.org domain works:

$ telnet gateway-s.comcast.net 25
Trying 204.127.202.26...
Connected to gateway-s.comcast.net.
Escape character is '^]'.
220 sccrmxc15.comcast.net - Maillennium ESMTP/MULTIBOX sccrmxc15 #57
helo localhost
250 sccrmxc15.comcast.net
mail from: <chris-blug at syntacticsugar.org>
250 ok
rcpt to: <abcdef at comcast.net>
550 [SUSPEND] Mailbox currently suspended - Please contact correspondent 
directly

So it seems the lookup is for an MX record since you have no A record. 
This is from my IP, so reverse lookups don't seem to be the problem.

Any way you can check on your DNS status when you've had problems?

HTH,
Dave