Nathanael Hoyle a écrit :
>
> I liked Jorey's idea enough to give it a shot. Actually implemented it
> yesterday. I debated about having the 'dead' MX host point at a system
> which dropped the requests but logged them (via iptables or similar),
> not so much to see how much legitimate email made it through (which
> seems to be pretty much all of it so far), but to see how much nasty
> traffic hit the primary 'dead' host that failed to retry on the second.
> For now, I have gone with a somewhat different approach. I actually
> have the primary MX listed as an IP that is a network boundary (and
> therefore flatly unusable),
what do you mean here?
the advantage I see is that the connect
> attempt will fail notably faster than it would if it had to time out,
> which reduces the burden on legitimate hosts, but is still just as
> undeliverable, keeping the desired effect. I will post with further
> results as I have the opportunity to observe them.
>
... what do you mean here? the advantage I see is that the connect...
mouss
usebsd@...
Nov 22, 2005 6:26 pm
... I'm using a host that has no A record (NXDOMAIN) as the dead primary in some of my configurations. While it applies less of a penalty, it isn't ...
Jorey Bump
list@...
Nov 22, 2005 6:40 pm
Guys, This is what I've setup: fauxmx01.plusone.com MX 10 (fake MX, non-responding <network> IP) nymeta01.plusone.com MX 20 (real MX) nymeta02.plusone.com MX...
Covington, Chris
Chris.Covington@...
Nov 22, 2005 9:59 pm
... no, this is different than GL: here, every host (legit or not) will try MX1, then if compliant, will try MX2. legit systems are thus somewhat penalized. In...
mouss
usebsd@...
Nov 23, 2005 1:20 am
... The theory behind GLing is that direct-to-MX clients won't retry, so if they time out at the primary MX or at the lowest-value MX that might be just as...
Covington, Chris
Chris.Covington@...
Nov 23, 2005 3:50 pm
... It's important to note that both methods exploit the lack of RFC-compliant behavior common to malware, albeit using completely different approaches....
Jorey Bump
list@...
Nov 23, 2005 4:51 pm
[...] ... Problem is that most low end "users"/mail administrator that handle only 3 or 4 mailboxes are mostly ignorant of the deal and the responsability ...
Xavier Beaudouin
kiwi@...
Nov 23, 2005 5:21 pm
... "most" is an understatement. ... How true. ... Instead, I've taken a different approach. I allow my customers to have ALL of my spam filtering, or NONE of...
Mark Nernberg
mark@...
Nov 23, 2005 7:09 pm
... The IP is a network boundary address. i.e., if it were a class C network (/24). the address would be x.x.x.0, rather than 1-254 or broadcast (255)....
Nathanael Hoyle
nhoyle@...
Nov 22, 2005 6:40 pm
... Oh yes it can. Your broadcast address is meaningful only for hosts on your subnet. Your broadcast address has no meaning for hosts on other subnets. Assign...
Wietse Venema
wietse@...
Nov 22, 2005 7:05 pm
... If you would please note, I used the bottom end network boundary, not the top-end broadcast address. To my understanding, this would be accurate in...
Nathanael Hoyle
nhoyle@...
Nov 22, 2005 7:09 pm
... It does not matter. The all-bits-0 (old broadcast) and all-bits-1 broadcast address have meaning only for hosts on your own subnet. The all-bits-0 (old...
Wietse Venema
wietse@...
Nov 22, 2005 7:19 pm
... - We live in CIDR. so remote client don't care. - broadcast and network addresses are valid (try a ping). so as Wietse says, packets will timeout, unless...
mouss
usebsd@...
Nov 22, 2005 7:25 pm
... The remote system has no idea how your network is subnetted. so the failure will mostly be caused by a routing error (no route to host) generated in your...