Grey-Listing ?
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Grey-Listing ? - 23.Nov.2006 3:56:27 AM
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mverheul@nem.nl
Posts: 2
Joined: 22.Nov.2006
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Call to all GFI users: Ask the supportdesk to include grey-listing antispam features to be implemented in the new-release of spam essentials!
Seen spam decrease with 99.98 percent! (using other grey-listing product)
Mike
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RE: Grey-Listing ? - 23.Nov.2006 10:13:39 AM
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messagetrust
Posts: 4
Joined: 6.Nov.2006
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I absolutely second this. So much spam seems to be sent as a one-off by bulk mailers and greylisting, by delaying the server response at the SMTP level, noting down the attempted connection, and waiting for the sending mail server to try again (which normal servers will) will stop this kind of spam as a lot of those mailers don't queue mail to be tried again. They'll have to rely on open relays which can then be blacklisted.
I've included a link (mostly for the GFI team so they have more info) to what greylisting is and how it works. My home email provider, softhome.net, uses it (among other things) and I get very few spam mails at home.
http://projects.puremagic.com/greylisting/
-dev...
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RE: Grey-Listing ? - 27.Nov.2006 3:20:54 AM
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Rolfie
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Joined: 27.Nov.2006
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Graylisting will unfortunately not survive. This works now very good, but for the spammers it’s easy to solve. Just retry it again. That solves the Graylisting problem for the spammers.
So Graylisting will stop at the moment a lot of spam, but in the future it will not. It’s too easy to resolve for the spammers. Most of the spam is being sent by bots or open relay servers, so bandwidth or CPU power is not a problem for the spammers. So they can retry as much as the want.
A better solution would be if a IP address send more than X times spam within X minutes, than block that IP for X minutes. This will stop more spam I think.
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RE: Grey-Listing ? - 27.Nov.2006 4:02:11 AM
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mverheul@nem.nl
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I know but this weekend alone 1 saved me from 3000 e-mails being delivered.
I found a free grey-listing add-on, for Microsoft environment (SMTP services / Exchange) "
Greylist v1.2.4
Mike
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RE: Grey-Listing ? - 27.Nov.2006 6:59:49 AM
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Mark Busuttil
Posts: 4833
Joined: 16.Oct.2005
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Thank you for your feedback, this has been added as a feature request!
_____________________________
Regards,
Mark Busuttil
GFI Software Ltd - www.gfi.com
Messaging, Content Security & Network Security Software
GFI: MailEssentials - MailSecurity - MailArchiver - FAXmaker - LANguard – WebMonitor
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RE: Grey-Listing ? - 28.Nov.2006 6:39:53 AM
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Mhuijgen
Posts: 41
Joined: 4.Aug.2005
From: Rotterdam
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quote:
ORIGINAL: Rolfie
Graylisting will unfortunately not survive.
That's no reason not to use it.
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RE: Grey-Listing ? - 28.Nov.2006 10:44:30 AM
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Ceth Eslick
Posts: 26
Joined: 2.Nov.2003
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Delaying spam should give the dnsbls more time to blacklist the offending computer.
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RE: Grey-Listing ? - 28.Nov.2006 3:52:15 PM
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Mats Bjur
Posts: 109
Joined: 9.Sep.2004
From: Gothenburg, Sweden
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I also agree. Graylisting is an effective spam-stopper and will be for at least some time. It should actually be an essential part of any anti-spam software. It also helps againt costly DNS lookups.
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RE: Grey-Listing ? - 29.Nov.2006 6:43:30 PM
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Roman Sandstorm
Posts: 2
Joined: 16.Nov.2006
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quote:
I found a free grey-listing add-on, for Microsoft environment (SMTP services / Exchange) "
Greylist v1.2.4
This looks quite interesting.
Has anyone actually implemented this with GFI ME?
What are the potential (negative) consequences of doing so?
Thanks...
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RE: Grey-Listing ? - 11.Dec.2006 7:05:00 PM
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pgreen
Posts: 14
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quote:
ORIGINAL: mverheul@nem.nl
I know but this weekend alone 1 saved me from 3000 e-mails being delivered.
I found a free grey-listing add-on, for Microsoft environment (SMTP services / Exchange) "
Greylist v1.2.4
Mike
Hi
Do you have this version installed currently? What is your GFI setup? Is GFI MailEssentials, MS Exchange and GreyList all installed on the same box?
I'm wondering if this product works with GFI MailEssentials.
Thanks... Paul
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RE: Grey-Listing ? - 12.Dec.2006 5:51:40 AM
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jw31
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Joined: 12.Dec.2006
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I thought I already posted a reply to this thread answering the above question, but it appears that either the reply never made it, or it got removed (possibly because I posted uncomplementary things about the lack of response from GFI regarding the provision (or lack) of a 30 day trial activation key).
Maybe Greylisting won't survive long-term, but for now it is doing a great job.
Things to watch out for are (again I'm sure I posted this) (1) The added 5 to 7 minute average delays that are introduced into the mail delivery process for non-white-listed connections and (2) if you have backup mailservers on other MX records for the domain then you'll need to greylist those too. Point (1) can be managed to a large extent by creating a decent white-list.
--------EDIT--------
Information on competitors was removed from this post.
Kindly keep the discussion to GFI products only.
< Message edited by Nicks -- 12.Dec.2006 9:03:11 AM >
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RE: Grey-Listing ? - 12.Dec.2006 10:22:27 AM
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Nicks
Posts: 2605
Joined: 17.Mar.2003
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Hi,
Although Greylisting is does have various advantages, it also has some disadvantages, some of which have already been discussed in this post. Below is a list of things that you need to watch out if you are implementing a greylist:
- It will introduce a delay for all the emails which are not known to the system.
- Not all mail servers implement the Temporary failure error correctly. This means that the sender of the message may receive an NDR for the message which has been greylisted.
- It can be a nuisance for web-sites that require registration (like forums), since the registration will be delayed.
- It is also relatively easy to circumvent, since spammers just need to start 'supporting' the Temp failure, which is given by a Greylist server.
_____________________________
Nicholas Sciberras
GFI Software - www.gfi.com
Messaging, Content Security & Network Security Software
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RE: Grey-Listing ? - 12.Dec.2006 10:56:25 AM
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RSP
Posts: 453
Joined: 31.Oct.2006
From: UK
Status: offline
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quote:
--------EDIT--------
Information on competitors was removed from this post.
Kindly keep the discussion to GFI products only.
Nicks, that was a highly inappropriate edit - If I remember correctly, there was no "competitor" reported on in that post. Indeed, although you reserve the right to delete messages, performing unilateral moderation in this manner is more likely to lose you customers than gain you respect. The views of the message author are just that, views.
If you can't disuade your users/potential customers from using a competitor's product by selling your own, then your product is obviously inferior and needs updating.
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RE: Grey-Listing ? - 12.Dec.2006 5:33:46 PM
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Ceth Eslick
Posts: 26
Joined: 2.Nov.2003
Status: offline
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I think the long run benefit of greylisting is the amount of time and resources it requires of the spamming computer. The longer it has to wait, the more time the DNSBLs have to catch it. Also, attempting to resend wastes the spammer's resources, which would otherwise be spent sending "successful" messages.
I think you can combine greylisting, SPF, and DNSBL to create a fairly effective anti-spam system. If the sender has a valid SPF record, it would be given a pass as far as greylisting is concerned (but not for any other check). This would encourage more people to use SPF. A lot of spammers use SPF, but that would make them easier to blacklist. Organizations and ISPs who don't want to use SPF because of whatever philosophical or economic reason don't have to -- but their email will be delayed.
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RE: Grey-Listing ? - 12.Dec.2006 5:48:40 PM
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Ceth Eslick
Posts: 26
Joined: 2.Nov.2003
Status: offline
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I forgot to mention that Greylisting has cut down incoming email by 70%. We use Mail Essentials in combination with ASSP (free) and the (free) "Greylist" utility. Both of these utilities can be installed on the same machine as Mail Essentials with some configuration. "Greylist" is easy to implement, but it doesn't have an autowhitelist. I installed it on our secondary/backup relay, since mail going through it is almost entirely spam. ASSP does autowhitelisting, so I installed it on our primary relay, which is also our smarthost.
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