On 06/25/2010 05:56 PM, Greg Woods wrote:
Historical thoughts on RBL:
You've had several suggestions so just a couple of comments. The
MAPS list (aka rbl) was an/the original DNSBL - if I remember right it
went weird a long back and required you fill out a long legal doc (with
a pen) which if your IP ever changed you needed to do the entire thing
over again. There was a 'free' and a pay service.
It got too tedious to be useful - since then Trend Micro purchased
them and now sells the service - what is still easily accessible I dont
know.
The current way is to use the FEATURE(`enhdnsbl'). Many of these
lists share a huge overlap in common - so adding the first RBL is a huge
benefit - thereafter you may find little to no further benefit for each
additional RBL you add. There is some cost to adding them tho' smallish
for a home / small business site.
Here are some of the things I do (feel free to ignore!) ... for me
spam is not zero but but it mostly quiet - every now and again I get a
new spurt of a few a week then it goes quiet again.
1) FEATURE(`enhdnsbl', `bl.spamcop.net', `', `t', `127.0.0.2.')dnl
2) FEATURE(`greet_pause', `3000')dnl
I found 3 secs to work well for me you may tune as you see fit.
** 3) FEATURE(`block_bad_helo') dnl
** 4) FEATURE(`require_rdns') dnl
5) Maintain access list -
- mine contains (large) number of netblocks
- use senderbase to help identify netblocks and get more info
about IP's.
http://www.senderbase.org
- only look at the last Received line hitting your mail server
You may choose what you want to block here - e.g. residential IP's
6) I have also iptable Firewall blocks for undesirables (I use some
country blocks in addition to a list of naughties)
7) run spamassasin (at the back end not the border server if you're
running internal and border sendmails).
Good luck ... :-)
gene
** you will need FEATURE(delay_checks)dnl
as well.