dhcpd ddns request 1 sec timeout

[Seiji T]

Glenn,

Thanks for the response.

> The dhcp server is single threaded, so it blocks while the dns update
> is done. If it waits too long it may miss other incoming dhcp requests.

I understand that but then, why is 1 sec okay and not 2 sec? Why not 500 msec?


> If your incoming dhcp rate is pretty low then there should be little
> harm in bumping the timeout up to two seconds. But really you should
> look at your DNS infrastructure and see if there is a way to improve
> it's response.

Maximum possible rate will be like 7000 DHCP requests at once to 2
dhcp servers.

As you have suggested, we are planning to change our DNS
infrastructure. Currently the DDNS server transfers full zone data to
approx 20 secondary servers everytime DNS database changes. We are
thinking of relaying via a hub server which will then transfer the
full zone data to the 20-something secondary servers. We thought of
incremental zone transfer but we never done it before  and decided
that relaying to one server is safer. We are waiting for management to
give us the "go" sign.

We are looking at other options and the purpose of this thread is to
understand the rationale behind the 1 sec fix.

Thanks,
  Seiji T.

On 12/27/06, Glenn Satchell <Glenn.Satchell at uniq.com.au> wrote:
> >Date: Wed, 27 Dec 2006 14:32:42 +0900
> >From: "Seiji T" <mlbots at gmail.com>
> >To: dhcp-users at isc.org
> >Subject: dhcpd ddns request 1 sec timeout
> >
> >Hello all,
> >
> >Is there any rationale to setting the default dhcpd ddns timeout to 1
> >sec and not 2 sec? I am using dhcpd 3.0.3 .
> >
> >I am seeing my dhcpd ddns request being failed b/c of the 1 sec
> >timeout. I did some packet sniffing and it seems that a lot of the
> >ddns server response takes just a little over 1 sec (<<2 sec). I am
> >wondering what kind of effect it might have if I set it to 2 sec. The
> >reason I am wondering and not doing is b/c I can't replicate the
> >production enviroment due to resource issues.
> >
> >I would love to hear from people who tried different timeout values.
>
> The dhcp server is single threaded, so it blocks while the dns update
> is done. If it waits too long it may miss other incoming dhcp requests.
>
> If your incoming dhcp rate is pretty low then there should be little
> harm in bumping the timeout up to two seconds. But really you should
> look at your DNS infrastructure and see if there is a way to improve
> it's response.
>
> regards,
> -glenn
> --
> Glenn Satchell     mailto:glenn.satchell at uniq.com.au | Some days we are
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