On Tue, Aug 3, 2010 at 3:51 PM, andrew colin <[email protected]> wrote:
> > What you decide is up to you, if you are okay with delaying legitimate mail > to "make life hard" for spammers then well go for it. > My experience how ever is you can keep spam under control without > greylisting. > > As mentioned before, an intelligent implementation of greylisting will cater for this as well. That is why its called greylisting. You grey-list an IP address that has connected to you once and when it comes back to re-try the delivery after a given amount of time has elapsed, then you whitelist that IP address for a duration of your choice. If they do not come back, then you may opt to drop the IP address from your grey list or blacklist it if it has repeat occurrences of connecting and not returning after a delay. There are numerous ways of cutting down on spammers, reverse DNS look up on the senders IP address, RBL's, callbacks, greylisting, tarpits... I would not say it is wise to dismiss one just because you do not see its need or purpose. I would say to Bright, test all the ways out there to reduce on spam and virus emails and see which works best for you. > > On Tue, Aug 3, 2010 at 2:43 PM, Bright Onapito <[email protected]>wrote: > >> Andrew, >> Are you saying that I don't need to install Postgrey? All I have to do is >> add this to which file- /etc/postfix/main.cf? Kyle, any comment on this? >> Thanks, >> Bright >> >> >> On Tue, Aug 3, 2010 at 3:37 PM, andrew colin <[email protected]>wrote: >> >>> >>> Postfix which the user has already has a built in mechanism to stop that >>> dictionary like delivery, >>> you do not need greylisting for that. >>> >>> smtpd_error_sleep_time = 5s >>> smtpd_soft_error_limit = 10 >>> smtpd_hard_error_limit = 20 >>> >>> Most spammers do not use systems under their own administration so why >>> would they care if >>> the mail queue filled up ? >>> >>> >>> On Tue, Aug 3, 2010 at 1:42 PM, Kiggundu Mukasa <[email protected]>wrote: >>> >>>> >>>> Grey listing works because its a pain in the arse of spammers >>>> I have used it and it works very well >>>> >>>> Agreed that any decent smtp implementation will resubmit >>>> BUT >>>> imagine you are trying to deliver tens of millions of messages and they >>>> are just queuing up because of retransmission >>>> >>>> On more than one of the servers I control I have seen spammers sending >>>> to every name (in alphabetical order) in the english language. >>>> so you can get >>>> >>>> [email protected] >>>> [email protected] >>>> [email protected] >>>> [email protected] >>>> etc >>>> etc >>>> etc >>>> until >>>> >>>> [email protected] >>>> >>>> Imagine they are doing that for many domains >>>> >>>> That type of spammer cannot afford to be told that for each delivery >>>> wait for 5 minutes ....they hardly ever resend. >>>> >>>> Kiggs >>>> >>>> >>>> >>>> >>>> On Aug 3, 2010, at 1:25 PM, andrew colin wrote: >>>> >>>> Greylisting is a brain dead idea any decent smtp implementation will >>>> not be detered from resubmitting, +1 for spamhaus. I say go >>>> spamassassin, kaspasky never worked for us too. Block most stuff at >>>> MTA level using RBL, reverse DNS checks, sane security signatures, >>>> then scan only stuff that got through those checks. >>>> >>>> On Tue, Aug 3, 2010 at 10:43 AM, Kyle Spencer <[email protected]> >>>> wrote: >>>> >>>> Bright, >>>> >>>> >>>> I recommend using a technique called "greylisting" combined with a >>>> zen.spamhaus.org RBL check. This will effectively kill 95-99% of your >>>> spam with no danger of false-positives. >>>> >>>> >>>> Greylisting on a Postfix system can be implemented with a package called >>>> "postgrey" and the zen.spamhaus.org RBL is a config line change or two >>>> away. >>>> >>>> >>>> Here's links to some how-to's: >>>> >>>> http://www.komaii.com/linux/postgrey-on-SuSE10.2/ >>>> >>>> and >>>> >>>> http://www.spamhaus.org/zen/ >>>> >>>> and >>>> >>>> http://wiki.debian.org/Postfix#anti-spam.3AUsingRBLLists >>>> >>>> >>>> There are probably better tutorials around since I just picked the first >>>> reasonable looking one on Google, but give it a try and let us know if you >>>> run into problems. >>>> >>>> >>>> Regards, >>>> >>>> Kyle Spencer >>>> >>>> >>>> ----- Original message ----- >>>> >>>> Hello Everyone, >>>> >>>> Is it OK to run Spam Assassin along side Kaspersky Anti Spam? How >>>> >>>> effective is Spam Assassin? My mail server is being bombarded with >>>> >>>> alot of spam. I am currently using Kaspersky Anti Spam but it seems >>>> >>>> not to be doing a good job. >>>> >>>> I use Postfix as my MTA on OpenSuSE 10.3. I need a solution, any ideas? >>>> >>>> Thanks, >>>> >>>> Bright Onapito >>>> >>>> "-If you want to see change, then be that change." >>>> >>>> _______________________________________________ >>>> >>>> LUG mailing list >>>> >>>> [email protected] >>>> >>>> http://kym.net/mailman/listinfo/lug >>>> >>>> >>>> LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ >>>> >>>> >>>> All Archives can be found at >>>> http://www.mail-archive.com/[email protected]/ >>>> >>>> >>>> The above comments and data are owned by whoever posted them (including >>>> >>>> attachments if any). The List's Host is not responsible for them in any >>>> >>>> way. --------------------------------------- >>>> >>>> >>>> >>>> _______________________________________________ >>>> >>>> LUG mailing list >>>> >>>> [email protected] >>>> >>>> http://kym.net/mailman/listinfo/lug >>>> >>>> >>>> LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ >>>> >>>> >>>> All Archives can be found at >>>> http://www.mail-archive.com/[email protected]/ >>>> >>>> >>>> The above comments and data are owned by whoever posted them (including >>>> attachments if any). The List's Host is not responsible for them in any >>>> way. >>>> >>>> --------------------------------------- >>>> >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> "Dru" >>>> To follow the path, look to the master, follow the master, walk with >>>> the master, see through the master, become the master. (zen) >>>> http://www.topdog.za.net/ >>>> http://www.baruwa.org/ >>>> _______________________________________________ >>>> LUG mailing list >>>> [email protected] >>>> http://kym.net/mailman/listinfo/lug >>>> >>>> LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ >>>> >>>> All Archives can be found at >>>> http://www.mail-archive.com/[email protected]/ >>>> >>>> The above comments and data are owned by whoever posted them (including >>>> attachments if any). The List's Host is not responsible for them in any >>>> way. >>>> --------------------------------------- >>>> >>>> >>>> >>>> Sincerely, >>>> >>>> >>>> >>>> >>>> *Kiggundu Mukasa* >>>> >>>> SERVAL LTD. >>>> Plot 80 Kanjokya Street >>>> P.O. Box 24284 Kampala, Uganda >>>> Tel: +256 772 972255 >>>> +256 414 571779 >>>> Fax: +256 312 262122 >>>> >>>> http://serval.ug >>>> >>>> >>>> >>>> _______________________________________________ >>>> LUG mailing list >>>> [email protected] >>>> http://kym.net/mailman/listinfo/lug >>>> >>>> LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ >>>> >>>> All Archives can be found at >>>> http://www.mail-archive.com/[email protected]/ >>>> >>>> The above comments and data are owned by whoever posted them (including >>>> attachments if any). The List's Host is not responsible for them in any >>>> way. >>>> --------------------------------------- >>>> >>>> >>>> >>> >>> >>> -- >>> "Dru" >>> To follow the path, look to the master, follow the master, walk with the >>> master, see through the master, become the master. (zen) >>> http://www.topdog.za.net/ >>> http://www.baruwa.org/ >>> >>> _______________________________________________ >>> LUG mailing list >>> [email protected] >>> http://kym.net/mailman/listinfo/lug >>> >>> LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ >>> >>> All Archives can be found at >>> http://www.mail-archive.com/[email protected]/ >>> >>> The above comments and data are owned by whoever posted them (including >>> attachments if any). The List's Host is not responsible for them in any way. >>> --------------------------------------- >>> >>> >>> >> >> _______________________________________________ >> LUG mailing list >> [email protected] >> http://kym.net/mailman/listinfo/lug >> >> LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ >> >> All Archives can be found at http://www.mail-archive.com/[email protected]/ >> >> The above comments and data are owned by whoever posted them (including >> attachments if any). The List's Host is not responsible for them in any way. >> --------------------------------------- >> >> >> > > > -- > "Dru" > To follow the path, look to the master, follow the master, walk with the > master, see through the master, become the master. (zen) > http://www.topdog.za.net/ > http://www.baruwa.org/ > > _______________________________________________ > LUG mailing list > [email protected] > http://kym.net/mailman/listinfo/lug > > LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ > > All Archives can be found at http://www.mail-archive.com/[email protected]/ > > The above comments and data are owned by whoever posted them (including > attachments if any). The List's Host is not responsible for them in any way. > --------------------------------------- > > > -- Mike Of course, you might discount this possibility, but remember that one in a million chances happen 99% of the time. ------------------------------------------------------------
_______________________________________________ LUG mailing list [email protected] http://kym.net/mailman/listinfo/lug LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ All Archives can be found at http://www.mail-archive.com/[email protected]/ The above comments and data are owned by whoever posted them (including attachments if any). The List's Host is not responsible for them in any way. ---------------------------------------
