Mailing List CGatePro@mail.stalker.com Message #92354
From: Jeff Wark <jwark@tbaytel.net>
Subject: Re: Feature request: temporary greylist
Date: Tue, 28 Aug 2007 10:55:44 -0400
To: CommuniGate Pro Discussions <CGatePro@mail.stalker.com>
X-Mailer: CommuniGate Pro WebUser v5.0.13
Reading Wikipedia [http://en.wikipedia.org/wiki/Greylisting] I see that the one problem with greylisting is the requirement that the triples be remembered for a configurable period, perhaps a very long time [I was under the impression that they would just timeout and be forgotten again after the message was sent..should have thought it through].

On Tue, 28 Aug 2007 10:39:09 -0400
 Jeff Wark <jwark@tbaytel.net> wrote:
How does someone get on the greylist?

My understanding of greylisting was that if the to/from/ip triple had not been seen before, there would be a delay of a few hours.

So, with that [perhaps incorrect] understanding your features might be:

1) CLI functions to Add, Remove, and enumerate
Add would pre-add a triple to the list, pre-allowing it to send email without delay or a reduced delay
Remove would remove a triple from the list, making it unknown to the server and therefore forcing it to wait the whole delay period
enumerate - same.

2) If an IP doesn't exist in the temp greylist OR it does exist in the temp greylist but has not been delayed enough, issue a 4xx rejection.

3) Provide a method of time-expiring the greylist entries....same as before.

Again, this is based on my assumption of what greylisting is.

On Tue, 28 Aug 2007 07:01:01 -0700
 "Bret Miller" <bret.miller@wcg.org> wrote:
I think this has been requested before, but I'm going to do it again. Grey listing is being done more often, even by big servers like Yahoo and MSN/Hotmail as a method of reducing spam. Essentially the theory goes like this: we received spam from you, so we are now going to delay your email for a certain length of time. For many spammers, this is enough for them to give up delivering the spam.

I think this would be an easy feature to add to CGPro because it essentially already exists. The temporary blacklist works pretty much like a greylist would except it uses a 5xx rejection code instead of a 4xx code.

Here's how this feature would work in CGPro:

1. Provide CLI functions to add, remove, and enumerate the temporary greylist.

2. If an IP exists on the temp greylist, issue a 4xx rejection for the message before the data phase.

3. Provide a method of time-expiring the greylist entries, and settings that control the length of time IPs remain on the list.

4. (Optional) provide a rule action to "Add to greylist" so that admins could add IPs to the greylist based on results from external helpers.

Thanks,
Bret




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Jeff Wark
TBayTel Internet

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