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Date:  Thu, 12 Jul 2007 02:59:19 +0300
From:  Arthur Sherman <arturs (at mark) netvision.net.il>
Subject:  [coba-e:10383] Re: more than 1 mx record or not
To:  coba-e (at mark) bluequartz.org
Message-Id:  <010e01c7c417$7ef8b970$3701a8c0@user33b5201c50>
In-Reply-To:  <008901c7c40d$0dbda5e0$010210ac@DELLBOY>
X-Mail-Count: 10383

Assuming we have 2 MXs in 2 different ISP, and we want to make a client
choose the nearest MX: how (if at all) this could be achieved?

Best,

--
Arthur Sherman
052-4878851
 

> -----Original Message-----
> From: Hugh Messenger [mailto:hugh (at mark) alaweb.com] 
> Sent: Thursday, July 12, 2007 1:45 AM
> To: coba-e (at mark) bluequartz.org
> Subject: [coba-e:10381] Re: more than 1 mx record or not
> 
> If you are load balancing rather than providing a "secondary" 
> (backup) MX of a lower priority, the only thing I would add 
> to what Chris said is the choice between publishing 2 MX's 
> with the same priority, or a single MX which points to a 
> round-robin'ed pair of A records.
> 
> If you publish two MX's of the same priority, it is up to the 
> sending side to pick one "at random".  However, there are 
> quite a few broken MTA's out there which will always use the 
> first one in the list, so your load balancing will tend to be skewed.
> 
> By publishing a single MX which points to a round-robin'ed 
> pair of A records (i.e. two A records with the same hostname 
> but different IP's), then you control the load balancing, 
> rather than the remote MTA's, and you usually find that the 
> balancing is more even.
> 
> The down side of using the round robin A record is that if 
> one of them dies and you have to take it out of the rotation 
> while you fix it, remote MTA's won't pick up on the other one 
> till the TTL for that record expires.
> 
>    -- hugh
> 
> 
> > -----Original Message-----
> > From: Chris Gebhardt - VIRTBIZ Internet 
> > [mailto:cobaltfacts (at mark) virtbiz.com]
> > Sent: Wednesday, July 11, 2007 5:14 PM
> > To: coba-e (at mark) bluequartz.org
> > Subject: [coba-e:10378] Re: more than 1 mx record or not
> > 
> > Steffan wrote:
> > > Hello List,
> > >
> > > Just wondering.
> > > im using grey listing etc
> > > And using 2 mail servers for my clients domains But reading on 
> > > Internet I see more posts that say that today the day Is 
> is better 
> > > not to use more than one mx record for a domain But just 
> use one mx 
> > > record When this is down the mail bounces back but the 
> server will 
> > > try again
> > later
> > >
> > > Im just wondering what the ideas of the experts are in 
> the list :-) 
> > > Do you stil need today more then one mx record for a domain ?
> > 
> >  From what I have seen, this advice is given because the author 
> > assumes that the spam filtering on the "secondary" will be less 
> > effective than what is on the "primary" MX.
> > 
> > In my experience, there are many spammers that will intentionally 
> > ignore the MX preference, or actually use the lower 
> preferenced MX to send mail
> > to a domain.   The thought process is that the spam 
> filtering may get
> > bypassed in this way.
> > 
> > We run 2 MX relays for all of our virtual hosting 
> customers.  They are 
> > 2 separate systems in 2 different datacenters and 2 
> different networks.
> > Both servers run the same filtering rules, and sync themselves every
> > hour.  So no matter which MX is used, the filtering is the 
> same.   If
> > something ever happens to one of the MX's, the other is 
> standing by, 
> > and there is NEVER a bounce or a delay.
> > 
> > Everybody has their own opinion, but obviously, my company 
> feels that 
> > 2 MX's with identical configurations is preferable to a 
> single point 
> > of failure.
> > 
> > However, if you were in a situation where your primary MX 
> was the spam 
> > filtering system and the secondary was not filtered, then 
> go with the 
> > single MX and save yourself and your customers from the spam.
> > 
> > --
> > Chris Gebhardt
> > VIRTBIZ Internet Services
> > Hosting, Collocation, Dedicated Servers, Internet Access
> > (972) 485-4125 | http://www.virtbiz.com
> 
> 
> 
>