DNS in network.wan.dns or in network.lan.dns?

Installing and Using OpenWrt Network and Wireless Configuration
1

Hello,
I have an EdgeRouter X with OpenWrt 18.06.5.
Router WAN port is connected with static IP to my ISP gateway in DMZ and LAN ports to my LAN stuffs.

Current config:
uci show network.lan
network.lan=interface
network.lan.type='bridge'
network.lan.ifname='eth0.1'
network.lan.proto='static'
network.lan.netmask='255.255.255.0'
network.lan.ip6assign='60'
network.lan.ipaddr='10.0.0.1'

uci show network.wan
network.wan=interface
network.wan.ifname='eth0.2'
network.wan.proto='static'
network.wan.ipaddr='192.168.1.1'
network.wan.netmask='255.255.255.0'
network.wan.gateway='192.168.1.100'
network.wan.dns='1.1.1.1 1.0.0.1'

I have configured the DNS under WAN interface and everithing work fine.
Should I add also network.lan.dns='1.1.1.1 1.0.0.1'?
What is the difference having the DNS under lan section only, under wan section only or under both interfaces?

2

I have a pppoe based WAN connection and DNS in WAN settings. I think it should work this way. But you can also try DNS hijack in documentation.

3

It is the DNS to be used by the router, and should be configured on the interface where it can be reached.

3 Likes
4

The linux systems use /etc/resolv.conf to specify nameservers and options.
In the case of OpenWrt, it is symbolic link to /tmp

root@koutsomoura:~# ls -la /etc/resolv.conf 
lrwxrwxrwx    1 root     root            16 Jun 27 14:18 /etc/resolv.conf -> /tmp/resolv.conf

In /tmp however there are a few resolv.* files. Do a head -n -0 /tmp/resolv.* to check them all.
In a nutshell /tmp/resolv.conf will be using 127.0.0.1 as nameserver, that means the local dnsmasq, and there is also an option for search domain. (default is lan)
/tmp/resolv.conf.INTERFACE will contain the NS that you configured or were automatically acquired (from ppp or dhcp)
/tmp/resolv.conf.auto contains a collection of the available NS from all the interfaces (if enabled) and is by default used by dnsmasq for resolving.