Hello, 

> Instead, the upstream anti-spam RBLs are disappearing entirely (perhaps 
> due to DDoS attack), so after the local cache entry expires, our local 
> cache gets no response from the RBL and thus obtains nothing to cache, 
> whence lookups to the local cache for those entries end up hanging until 
> they time out.

I don't think there is a way in exim to change its TTL rate. 

Increasing the DNS TTL might work, but you still have the issue of the TTL 
timeout being reached. A private list of non-responsive RBLs then is the 
best option.  You'll have to devise some way of testing the RBLs (out side 
of Exim) periodically to determine in they are back online. 

 --- 

DynaStop: Stopping spam one dynamic IP address at a time.
http://tanaya.net/DynaStop/

-- 
## List details at http://lists.exim.org/mailman/listinfo/exim-users 
## Exim details at http://www.exim.org/
## Please use the Wiki with this list - http://wiki.exim.org/

Reply via email to