DHCPD issue parameters

Harald Schöner harald.schoener at mygate.net
Sat Apr 14 12:32:55 UTC 2012


This is a misbehavior of the DHCP client, as it doesn't look at the changed
options during
a renew of its lease.

This has been observed with many dhcp clients, even the isc one.



On 13 April 2012 23:25, Teva AVRIL-TEIPOARII <teva at viti.pf> wrote:

>
> Greetings,
>
> I've got a dhcpd server, which is working good. However i've got an issue:
> i've modified one parameter on the dhcpd.conf for one subnet (i've changed
> option domain-name-servers ip), i've restarted the dhcpd service.
>
> My issue is i've got an ip address, but not the update DNS-servers.
>
> Here below configuration of the dhcpd.conf before modification:
>
> shared-network test {
> option domain-name "test.com";
> option domain-name-servers 192.168.1.2, 192.168.1.3;
> default-lease-time 360;
> max-lease-time 360;
>
> subnet 192.168.10.0 netmask 255.255.255.0 {
> option routers 192.168.10.254;
> option subnet-mask 255.255.255.0;
> option broadcast-address 192.168.10.255;
> }
>
> pool {
> range 192.168.10.1 192.168.10.253;
> }
> }
>
> And now after modification:
>
> shared-network test {
> option domain-name "test.com";
> option domain-name-servers 192.168.45.1, 192.168.1.3;
> default-lease-time 360;
> max-lease-time 360;
>
> subnet 192.168.10.0 netmask 255.255.255.0 {
> option routers 192.168.10.254;
> option subnet-mask 255.255.255.0;
> option broadcast-address 192.168.10.255;
> }
>
> pool {
> range 192.168.10.1 192.168.10.253;
> }
> }
>
> And here below global parameters applied to all subnets:
>
>
> ddns-update-style none;
> authoritative;
> log-facility local7;
> update-static-leases on;
>
>
>
>
> The result is that instead of having 192.168.45.1 and 192.168.1.3 as
> primary
> and secondary DNS, i still got 192.168.1.2 and 192.168.1.3 as primary and
> secondary DNS.
>
> I've deleted dhcpd.leases , thinking that maybe the issue could come from
> some leases not expired, but result is the same.
>
> I've performed a wireshark capture, and during the DORA process, i see that
> the DHCP server is sending the update DNS as it should. However on my PC
> (on
> Windows), i still see old DNS servers attributed (attribution is automatic,
> it's not in static on network configuration of the PC).
>
> I don't understand where this problem come from, if you have an idea,
> please
> let me know.
>
>
>
> _______________________________________________
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
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