How to clear the DNS cache

[Frank de Vries]

We have several HPUX server 11.i and 11.0
And we have an DNS server.
We are doing some tests and we would like
to know if a command or methode exists to
clear the DNS cache on our servers.

Thanks

[Joel Girot]

Hi Franck

rndc flush

see man rndc

Joel

[spex]

Hi Frank,

See Geoff Wild's response in this thread:
http://forums1.itrc.hp.com/service/forums/bizsupport/questionanswer.do?threadId=993552

PCS

[Steven E. Protter]

Shalom,

Indirectly changing the serial number on the zone record should trigger an immediate flush for that zone on all clients.

2006051301 becomes 2006091201 (today's date change 1).

Then restart bind.

Editing the zone records may be rough on named 4.9.7, I hope you are using Bind 8 or 9.

SEP

[Geoff Wild]

rndc flush

or stop/restart bind

Rgds...Geoff

[Frank de Vries]

When I try to man mdc it doesn't work or
exist ?
Where can I find the executable ?

[root@orasrv1:]/picnew/export/tp/backup/tp<>>> man mdc
No manual entry for mdc.
[root@orasrv1:]/picnew/export/tp/backup/tp<>>

[Joel Girot]

not mdc but RNDC in lowercase : rndc
man 1 rndc

Joel

[spex]

Hi Frank,

/usr/sbin/rndc

R N D C

PCS

[Frank de Vries]

Is that standard on 11.i ?
I do not have it on any of my machines,
which include a couple of 11.00 also.

[vwbsrv1:/root]# ls -altr /usr/sbin/mdc
/usr/sbin/mdc not found
[vwbsrv1:/root]#

Where can I download this or get this ?

[Joel Girot]

it is standard on 11i Franck but it is not mdc (MDC) but rndc (RNDC : r n d c)
$ ls -altr /usr/sbin/rndc
lrwxr-xr-x 1 root sys 31 Jan 18 2005 /usr/sbin/rndc -> /usr/contrib/bind/usr/sbin/rndc
Joel

[Frank de Vries]

Sorry about that, I am not paying attention to well.

In any case I tried the rdnc too
[vwbsrv1:/root]# ls -altr /usr/sbin/rndc
/usr/sbin/rndc not found
[vwbsrv1:/root]# ls -altr /usr/contrib/bind/usr/sbin/rndc
/usr/contrib/bind/usr/sbin/rndc not found
[vwbsrv1:/root]#

Still no joy.

I wonder why we do not have it.
Did I miss something during the installation years ago ??

[Joel Girot]

In my hpux 11.11 box rndc come with bind (v920)
# swlist -l product | grep -i bind
BINDv920 B.11.11.01.006 BIND 9.2.0 special release upgrade
PHKL_32038 1.0 Psets Enablement, Kernel Binding
PHNE_30068 1.0 Bind 8.1.2 Patch

[Frank de Vries]

Well thanks;
I seem to have nada

[vwbsrv1:/root]# swlist -l product | grep -i bind
[vwbsrv1:/root]# uname -a
HP-UX vwbsrv1 B.11.11 U 9000/871 2001097676 unlimited-user license
[vwbsrv1:/root]#

[Geoff Wild]

RNDC only comes with recent versions of Bind.

Depending on the versions you have installed, you may or may not have it...

What version of bind is running?

You can use dig (if installed):

dig @yourserver version.bind chaos txt

Or with nslookup:

nslookup -q=txt -class=CHAOS version.bind. yourserver

You could also just run a find command...

Rgds...Geoff

[Joel Girot · Accepted solution]

on client side I don't think that it have dns cache. Only on server side. No need to flush on client side. Possibly see your /etc/hosts file.

[spex]

Hi Frank,

For older verions of BIND,

# /sbin/init.d/named stop
# /sbin/init.d/named start

will flush the cache.

PCS

[Frank de Vries]

Mr Spex

Is /sbin/init.d/named supposed to be running
on each client, or is this only
necessary on the DNS server ??

[Joel Girot]

Only on dns server Frank.

[Frank de Vries]

All your answers make me understand
where I stand.

The problem is that here we have dns not
on hpux (I wish it was) but on Windows (yeak).

thanks