Re: [EXIM] Possible bug in hosts_lookup_nets ?

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Author: Richard Welty
Date:  
To: exim-users
Subject: Re: [EXIM] Possible bug in hosts_lookup_nets ?
At 11:54 AM 8/5/98 -0400, you wrote:
>On Wed, Aug 05, 1998 at 10:34:00AM +0100, Philip Hazel wrote:
>> How often is occasionally? I don't myself think this is a major issue,
>> but others may wish to argue otherwise.


>It may be overly complex but why not use the Time-To-Live value associated
>with the address in the DNS? After the TTL expires, an address is not
>guaranteed to be valid anyway, so that would be a good time to reload.


yes!

while TTLs are often up in the 24 hour range, when i transition a domain
name to a new ip address, i start shortening the TTLs a day in advance -- i
cut it to one hour, then, 24 hours later, i cut it to a small number (say 5
minutes), and then an hour after that, i can think about a reasonably clean
transition to the new IP.

in other words, TTLs do get manipulated intentionally for good reason.

but here's another issue: i always run a caching name server on any
mailhost that sees serious service. since it already implements all the
caching mechanisms per RFC, perhaps there should be an option:

ip_cache = no
ip_cache = yes

richard


richard

-- 
Richard Welty
NeWorks Networking, Inc.                                  518-244-9675
rwelty@???                             http://www.neworks.net/



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