[Users] DNS caching

[Mahesh Paolini-Subramanya]

I second Klaus in this.
I might add, it is pretty trivial to set up your 'local' copy of bind9 to timeout within whatever 'acceptable' period you so desire (i.e., so as to prevent 'INVITE hangs', etc.).


cheers
----- Original Message -----
From: Klaus Darilion <klaus.mailinglists at pernau.at>
To: Christian Schlatter <cs at unc.edu>
Cc: users at openser.org
Sent: Monday, February 12, 2007 2:40:59 PM GMT-0600
Subject: Re: [Users] DNS caching

I wonder why you need DNs caching inside openser. Usually you will a
resolving name server near (in terms of network hops) to your SIP proxy.

E.g. I have a bind9 running on the same linux box as openser.  This name
server will be used by all processes running on this linux box
(/etc/resolv.conf points to 127.0.0.1 and to another name server in my
server farm).

Bind will cache all requests. A request for a domain which is cached in
bind will usually be <1ms and during waiting for the DNS response openser
wont cause CPU load - and probably the caching implementation in bind is a
good one.

Thus for me I do not see any reason for having the caching inside the SIP
proxy.

regards
klaus


On Mon, February 12, 2007 20:22, Christian Schlatter said:
> Now that OpenSER supports NAPTR/SRV lookups I'd like to add DNS caching
> to our SIP servers in order to decrease call setup delays and DNS server
> load introduced by DNS queries.
>
> I was wondering if others on this list have experience with running
> OpenSER together with a DNS cache solution like nscd or dnsmasq. Initial
> tests with nscd were not successful since somehow the OpenSER processes
> do not go through the ncsd caching, whereas e.g. ping does. I'm also not
> sure if ncsd or dnsmasq do support NAPTR and SRV type DNS queries.
>
> I'd be glad to hear any recommendations on this topic,
>
> Christian
>
> _______________________________________________
> Users mailing list
> Users at openser.org
> http://openser.org/cgi-bin/mailman/listinfo/users
>



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