DNS server reply timeout/retry

[viseth]

Hi everyone,

Does someone know how to change the DNS reply timeout and the DNS number of retries? I have a DNS client that does not wait long enough for a answer from a given DNS server and does not attempt to retry it query to the given DNS server, so that it send that query to another DNS server.

Many thanks for your feedback!

regards,

\Viseth

[A. Clay Stephenson]

Do a man 4 resolver; it will explain how to do this.

[A. Clay Stephenson]

I should also add that in addition to changes in /etc/resolv.conf you can also set and export these environment variables:

RES_RETRANS=3000 # milliseconds
RES_RETRY=5

These are explained in the man 3n resolver man pages.

[viseth]

But I do not find thoses parameters when I do a man resolver... Besides, do those parameters need to be set directly in the /etc/resolv.conf??

many thanks
regards,

\Viseth

[viseth]

Hi A. Clay Stephenson,

Thanks for the answer, I've found on internet the man 3n resolver pages. On my unix (solaris 2.8) the man does not states thoses parameters... maybe the version of the resolver is not the same, isn't it?

Regards,

\Viseth

[A. Clay Stephenson]

There is a difference between "man resolver" and "man 4 resolver" or "man 3n resolver".

In any case, you can set the environment variables as I indicated or you can add these entries to /etc/resolv.conf.

retry 6
retrans 6000

Note: The values in /etc/resolv.conf have higher precedence than the corresponding environment variable settings.

[viseth]

Hi A. Clay Stephenson,

Thanks for the reply! Do you know if it is possible to do the same with microsoft DNS client?

Many thanks,

Regards,

\Viseth

[Florian Heigl (new acc)]

One addition: These parameters are supported by all HP-UX versions >=11.11, for 11.00 You need two specific patches.
They're no hassle, but one requires a reboot.

In any case it's worth the effort.

[viseth]

Is this parameters supported as well for other plate-forms solaris, aix...
many thx

\Viseth

[Brian Hackley]

Viseth,

Solaris does support the retry/retrans also. At 2.6, the syntax there is retry:1 retrans:1000.

My typical recommended values for typical customer environment is 1 retry after 1 second / 1000msec. Your milage will vary.

For those of you missing the info from the HP-UX resolver() man page it is because it was missing until the libc man page patch is installed. 11.0 patch PHCO_24904 (latest is PHCO_31919) 11.11 patch PHCO_24915 (latest is PHCO_29829).
No patch needed for 11.23, it's man page also has the info.

HTH,

Brian Hackley