smtp load balancer???

[Denis Beauchemin]

    [ The following text is in the "ISO-8859-1" character set. ]
    [ Your display is set for the "US-ASCII" character set.  ]
    [ Some characters may be displayed incorrectly. ]

Chris Conn wrote:

>>
>> Chris,
>>
>> I've been told (and have verified it on many occasions) that big ISPs 
>> don't care about the TTL we define for our DNS entries.  They will 
>> override our TTL with their default value which could be as high as 
>> many days...
>
>
> Remember I am suggesting SLB over DNS...
>
> but,
>
> I am curious on verifying your claim as well as the other gentleman.  
> Are you defining the TTL on a per-record basis?  How are you doing this?
>
> Currently your TTL for record smtpe1.usherbrooke.ca is 1 day...how do 
> you go about overriding this?
>
> I do not believe that any ISP is "overriding" TTLs.  I would believe 
> non-compliant DNS servers perhaps.   But my testing locally here of 
> temporarily disabling my secondary DNS record for my MX shows that 
> Microsoft clients are flawlessly balancing to the remaining host.
>
> Your mileage may vary, but it works here.  Again I repeat that I do 
> not depend on this to spread load however, SLB does that nicely for me.
>

Chris,

I don't know exactly how they do it (the network guys).  I know that 
when moving anything important we keep the old and new IP for at least 1 
week, even if the TTL for that host has been lowered significantly (yes, 
it applies only to that host).

And our Windows clients have to have their DNS cache flushed AFTER the 
Windows servers have done it, otherwise they get the old IP back...

Maybe we just have things misconfigured, but I have no control over them 
(other teams).

Local ISPs that seem to override our TTL are videotron and sympatico.  
Two biggies!

Denis

-- 
   _
  °v°   Denis Beauchemin, analyste
 /(_)\  Université de Sherbrooke, S.T.I.
  ^ ^   T: 819.821.8000x2252 F: 819.821.8045

------------------------ MailScanner list ------------------------
To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
'leave mailscanner' in the body of the email.
Before posting, read the Wiki (http://wiki.mailscanner.info/) and
the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).

Support MailScanner development - buy the book off the website!