On 07/09/12 16:13, Steve Holdoway wrote:
As you've been very helpful in the past, can I ask the best way forward in addressing this problem.
In an attempt to reduce spam delivery to a local charity mail server, I added
FEATURE(`require_rdns')dnl
to the sendmail config. It did help. However, it also blocked some important clents as well...
barnardos.org.nz - sends via 122-56-8-123.cid.global-gateway.net.nz logon.i.govt.nz - has no IP address ecan.govt.nz - sends via onyx.crc.govt.nz which has no IP address
probably being the most important.
How do you address this problem. I'm certain they all must have been repeatedly contacted?
TIA for all ideas
Hey Steve, That list of unmatched/missing rdns is the just the tip of the iceberg - especially with the government departments. Requiring reverse DNS is something we attempted years ago but the amount of legitimate e-mail that was blocked (especially a lot of those .govt.nz domains) meant it didn't last longer than a whole day. Even though it's the other guys doing it wrong it's hard to explain to customers that are quick to say "it works for ISP X, why not you guys?" Indeed, the "proper" solution would be to try and chase up those providers but it is hard to justify the time. Are you using greylisting? That still nets some good results still - stripping out the low hanging fruit before being processed by traditional spam filtering. - Damian -- Damian Kissick Actrix Networks Ph. 0800 ACTRIX #408 Mob. 027 251 1127 Fax. +64 4 801 5335 http://www.actrix.co.nz