Re: [exim] Is a secondary MX worth the effort?

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Συντάκτης: Mike Cardwell
Ημερομηνία:  
Προς: Exim Mailing List
Αντικείμενο: Re: [exim] Is a secondary MX worth the effort?
John W. Baxter wrote:

>> I don't know if it's still true,
>> but the mailer for Yahoo Groups used to immediately unsubscribe recipients if
>> a single message was attempted for a failed
>> primary (presumably they would try secondaries if they exist, but I don't
>> know).
> We learned about that Yahoo Groups habit very quickly when we first turned
> up greylisting. They seem to have changed--they have been retrying
> successfully for a couple of years when a new host (or subnet, usually) of
> theirs starts running into greylisting.
>
> But that doesn't mean that no server is brain dead, only that Yahoo Groups
> no longer seems to be.


I don't bother greylisting any host listed by list.dnswl.org lists. Any
machine on that list should be a real mail server. Taking a quick look
at a yahoogroups ip from my exim logs:

root@clayman:~# host 171.168.163.66.list.dnswl.org
171.168.163.66.list.dnswl.org has address 127.0.5.0

The .0 at the end represents:

- Legitimate mail server, may also send spam.

The '5' is less useful but describes the host as:

- Service/network providers

They also provide free unregistered rsync feeds to their rbldns data:

root@clayman:/etc/exim4/lists# grep yahoo list.dnswl.org.rbldnsd|head -1
66.94.225.0/24 :127.0.5.0:yahoo.com http://www.dnswl.org/search.pl?s=1376

MikeC2