Hi. In-Reply-To: <20170824074515.y4z2ummdigk2fcbn@kazuki.local>
On Thu, Aug 24, 2017 at 04:45:15PM +0900, Mark Fletcher wrote: > Is there any clever way to pass through the name server settings > the DHCP server provides, so that if the ISP should change its name > server IP addresses in the future, my local DHCP server would pass along > the new addresses when next asked? > > In other words, instead of specifying the name server addresses > explicitly in the dhcp.conf file, is there a way to specify that they > should be taken from the host the DHCP server is running on? Somewhat hackish, but straightforward way to achieve this is to redirect DNS requests from your LAN to correct DNS. Something like this should do the trick: iptables -t nat -A OUTPUT -i <LAN Port> -p udp --dport 53 \ -j DNAT --to-destination <ISP DNS>:53 iptables -t nat -A OUTPUT -i <LAN Port> -p tcp --dport 53 \ -j DNAT --to-destination <ISP DNS>:53 iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -p udp --dport 53 -j ACCEPT iptables -A FORWARD -p tcp --dport 53 -j ACCEPT PS Being in the similar situation I said 'screw it' and installed caching DNS alongside with DHCP on a firewall. It simplified that setup immensely. Reco
