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+--- Thread: Turn off Postgrey for 1 domain? (/thread-3659.html)
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Turn off Postgrey for 1 domain? - NetworkExpertise - 07-02-2008 02:04 AM
Is there a way to just turn off postgrey for 1 domain on my server? I have a customer complaining that his clients cannot email them because their PTR records are incorrectly setup so its blocking important email. Is this postgrey even a good solution to spam filtering? It seems to do more harm then good.
RE: Turn off Postgrey for 1 domain? - kurgans - 07-02-2008 04:09 AM
Hello,
Postgrey All they do is retain the post 30 minutes your problems in the PTR is the inverse of your host resolution, which does not have a name associated, this record should create your own IP, you must ask the resolution to reverse your IP , With that complete your problems, I have had this problem a long time in Reverse DNS.
I am very sorry my English but speak only Spanish
RE: Turn off Postgrey for 1 domain? - NetworkExpertise - 07-02-2008 04:16 AM
I control DNS on my server and the reverse records myself. This is not an issue on my end this is an issue with peoples mail servers being on dynamic blocks. Back to my original question is it possible to turn off Postgrey for 1 domain customer? Maybe I should just turn off postgrey completely and rely on spamassisin for filtering?
RE: Turn off Postgrey for 1 domain? - Cube - 07-02-2008 04:23 AM
Read the FAQ: http://www.isp-control.net/documentation/frequently_asked_questions/how_can_i_disable_postgrey_for_a_domain_or_mailadress
(IMHO postgrey is nonsense anyway
)
RE: Turn off Postgrey for 1 domain? - motokochan - 07-02-2008 07:12 AM
NetworkExpertise Wrote:I have a customer complaining that his clients cannot email them because their PTR records are incorrectly setup so its blocking important email. Is this postgrey even a good solution to spam filtering? It seems to do more harm then good.
Postgrey doesn't care what the PTR is on an IP, all it does is temporarily slow delivery the first time a mail arrives from a specific sender. What makes your client think postgrey is the problem?
Postgrey and greylisting in general are okay methods for dropping some spam. It was developed because a lot of the spam relays installed on compromised computers didn't follow standard mail practice and retry after a temporary (4xx) error.
The benefit is that if you provide a temporary error when being sent a mail the first time, this spam wouldn't ever reach your server. At the beginning, this dropped spam volumes about 60 - 80% in general. Newer spamming software is wise to this trick and actually will follow proper behavior, making this less effective, but a decent amount of spam is still being sent with the broken software. This lower volume means less spam to actually work your server CPU on, and increases the volume of mail throughput. It also lets you tune your filters to better fit the spam that does get through while not worrying about that other stuff.
RE: Turn off Postgrey for 1 domain? - NetworkExpertise - 07-02-2008 07:16 AM
Here is the output of the log files that help me determine this is a postgrey issue:
Jul 1 08:39:42 netxweb01 postfix/smtpd[30773]: NOQUEUE: reject: RCPT from adsl-75-51-129-101.dsl.pltn13.sbcglobal.net[75.51.129.101]: 450 4.7.1 <jason@this_is_my_customer.com>: Recipient address rejected: Greylisted, see http://isg.ee.ethz.ch/tools/postgrey/help/this_is_my_customer.com.html; from=<Carol@this_is_the_person_sending_to_my_customer.com> to=<jason@this_is_my_customer.com> proto=ESMTP helo=<this_is_the_person_sending_to_my_customer.com>
RE: Turn off Postgrey for 1 domain? - motokochan - 07-02-2008 08:25 AM
NetworkExpertise Wrote:Here is the output of the log files that help me determine this is a postgrey issue:
-- snip --
That's what it should look like. Note the error number is "450" which indicates the remote mail server should try again later. Usually there will be another attempt within 5 to 15 minutes. After that, the information is stored (from address, to address, ip) and any further communication will be allowed through.
Does the remote server every try back?
I know that MS Exchange 2003 and below didn't respond well to temporary errors at all and the message would sit in the SMTP queue until the server admin restarted the service. Service Pack 1 for Exchange 2003 fixed this issue (previous versions need a registry edit to fix the behavior).
(This kind of bad behavior is also why you should never let an Exchange server talk to the outside world.)
RE: Turn off Postgrey for 1 domain? - NetworkExpertise - 07-02-2008 08:27 AM
Actually I did see the remote server try again 2668 seconds later. It showed it came through cleanly, but the customer stated he never received the email. :/ Once i turned off postgrey the customer reported receiving emails just fine.
RE: Turn off Postgrey for 1 domain? - motokochan - 07-02-2008 08:35 AM
NetworkExpertise Wrote:Actually I did see the remote server try again 2668 seconds later. It showed it came through cleanly, but the customer stated he never received the email. :/ Once i turned off postgrey the customer reported receiving emails just fine.
That's really strange...
Were you able to trace the delivery all the way?
RE: Turn off Postgrey for 1 domain? - NetworkExpertise - 07-02-2008 08:37 AM
Didnt really waste my time on it if the customer calls once I lose money you know
