Re: [Sqlgrey-users] Backup MX servers

[Michel B. <mi...@bo...>]

Le Jeudi 16 Juin 2005 10:42, Ray Booysen a =E9crit :
>
> Why do you and Michael think that backup MX servers aren't neccesary? =A0
> Bouissou.net has 3 MX servers listed. =A0I don't understand why they ar=
e
> unneccesary.

All my 3 MXes (for my personal bouissou.net domain) are GNU/Linux compute=
rs=20
that are connected thru residential ADSL, so they might experiment=20
reliability or connectivity problems. Although it doesn't usually happen,=
 it=20
could, and that's why I use backup MXes.

I must stress the fact that I do have administrative control over all of =
those=20
(and actually 2 MX names currently point to the same IP address, one bein=
g=20
dynamic and set there for line backup purposes). Having administrative=20
control over all of my MXes allow me to guarantee that they implement the=
=20
same level of filtering, and greylisting on all.

The major (and only) advantages of having such backup MXes is that:

1/ In case the primary goes down, and mail gets queued on the secondary, =
when=20
the primary comes back I can get waiting mail immediately (using SMTP ETR=
N)=20
without having to wait for remote servers to retry at their own will with=
=20
their own schedule. For this to be useful, of course, you have to be able=
 to=20
perform ETRN on your secondaries.

2/ I can set a queue lifetime longer than the defaults on my secondaries,=
=20
which allows mail to stay waiting there "longer than normal" (usually 5 d=
ays)=20
without bouncing back,  in case I would experiment a very long primary=20
downtime for some reason (i.e. major hardware failure that I couldn't qui=
ckly=20
fix).


But in your case, if you state that you have no control over your seconda=
ries,=20
you probably cannot benefice from any of these features, and then the=20
baseline is that you shouldn't use thoses MXes over which you have no=20
control. All it can bring you is trouble.

--=20
Michel Bouissou <mi...@bo...> OpenPGP ID 0xDDE8AC6E