It is better to talk to the running BIND and let it do the change internally, you could use the 'nsupdate' tool for that, which is a rather crude thing but it works. I know, it might gave me any trouble, but luckily there's no trouble (as I seen) at all.
echo -e "update delete host.domain. \n" \ | nsupdate -k /etc/KDHCP_UPDATER.+157+59963.private echo -e "update add otherhost.domain. 86400 CNAME mydns.domain. \n" \ | nsupdate -k /etc/KDHCP_UPDATER.+157+59963.private Well the DHCP server can't know that the machine with the new NIC is the same as a previously seen NIC (unless you use client identifiers, but you won't do that). Otherwise you may use "one-lease-per-client true;" so the old leases and DNS names are cleaned up when a new one is requested by a known host.
I think I'm gonna use one-lease-per-client in my dhcpd.conf. Is there any problem if I use it ? maximum machine, etc ? BTW, here's my dhcp.conf ddns-update-style interim; ddns-updates on; one-lease-per-client true; ignore client-updates; include "/etc/named.keys"; include "/etc/rndc.key"; subnet 192.127.0.0 netmask 255.255.255.0 { option routers 192.127.0.1; option broadcast-address 192.127.0.255; option domain-name "fsi.info"; option domain-name-servers 192.127.0.18; option netbios-name-servers 192.127.0.1; ddns-domainname "fsi.info"; ddns-rev-domainname "0.127.192.in-addr.arpa"; range dynamic-bootp 192.127.0.180 192.127.0.254; default-lease-time 21600; max-lease-time 86400; zone fsi.info. {primary 127.0.0.1; key DHCP_UPDATER;} zone 0.127.192.in-addr.arpa. {primary 127.0.0.1; key DHCP_UPDATER;} And here's my named.conf zone "fsi.info" in { type master; file "dyn/fsi.info"; allow-update { key DHCP_UPDATER; }; }; zone "0.127.192.in-addr.arpa" in { type master; file "dyn/0.127.192.in-addr.arpa"; allow-update { key DHCP_UPDATER; }; regards, -- Arie Reynaldi Zanahar reymanx at gmail.com http://www.reynaldi.or.id