regex for dns update

Glenn Satchell glenn.satchell at
Tue May 8 13:56:06 UTC 2012

On 05/02/12 21:58, Tom Schmitt wrote:
> Hi,
> my dhcpd is sending DNS-updates to the DNS server when a lease is given to a dhcp client with the name the dhcp client is providing.
> Now I want this only if the name is following a given pattern, something like:
> if($clientname=~/^[A-Za-z]{4}\d{4}$/) {
>       send_dns_update;
> }
> else {
>       dont_send_a_dns_update;
> }
> Can anyone tell me, what the syntax is to configure this on a global scope in dhcpd.conf?
> Or a link where the syntax is explained?
> Thanks,
> Tom.

The syntax for 'if' and regex matches are explained in the dhcp-eval(5) 
man page.

Other useful DHCP man pages shipped with the ISC distribution are: 
dhcpd.conf(5), dhcp-options(5), dhclient.conf(5), dhcpd.leases(5) and 

There was a recent post (in the last month) that covered a similar 
topic, with some configuration that may be useful for you.

Glenn Satchell                            |  Miss 9: What do you
Uniq Advances Pty Ltd, Sydney Australia   |  do at work Dad?
mailto:glenn.satchell at         |  Miss 6: He just tel:0409-458-580   |  types random stuff.

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