Static leases with different DNS servers

Installing and Using OpenWrt Network and Wireless Configuration
1

Hi,

Is there any reason, why configuration like this in the /host/config/dhcp file

config host
option name 'mylaptop' # Hostname (optional, for reference)
option mac '11:22:33:44:55:66' # MAC address of the client
option ip '192.168.1.101' # Static IP to assign to the client
option dns '192.168.1.10' # Custom DNS server for this client*

could doesn't work, means custom DNS server is not assigned to the 'mylaptop' client?
Client still uses the default DHCP's DNS server..
Instead of 'option dns' I tried to use also
list dhcp_option '6,192.168.1.10'

In this way I would like to assign local custom DNS server (later also IPv6) to few DHCP clients, while keeping default external one for all others.

Thank you for any ideas...

Regards,
Franek

2

https://openwrt.org/docs/guide-user/base-system/dhcp_configuration#client_classifying_and_individual_options

3

That's not how it works, dns is a boolean telling OpenWrt to add it to the name server table so you can nslookup mylaptop. Details at https://openwrt.org/docs/guide-user/base-system/dhcp#static_leases

What you are looking for is probably in that same document, look at the sections above the one I linked.

4

Looks nice and simple... but doesn't work for me, still client use global one...
I've defined the tag1

dhcp.tag1=my_DNS
dhcp.tag1.dhcp_option='6,192.168.1.10' '23,fdaf:XXXX:XXXX:X:XXXX:XXXX:XXXX:XXX'

Added tag1 to few clients in Static Leases, but still they don't use 192.168.1.10, IPv6 one.. :frowning:

5

Post the dnsmasq config from /etc/config, mask any MACs.

6

See: https://github.com/egc112/OpenWRT-egc-add-on/tree/main/stop-dns-leak#option-6

That works for me

7

Thanks. Executed uci commands following

https://openwrt.org/docs/guide-user/base-system/dhcp_configuration#client_classifying_and_individual_options

... added almost the same configuration to my /etc/config/dhcp, except 'option dhcp_option...', but neither works with 'list dhcp_option...'

config my_DNS 'tag1'
        option dhcp_option '6,192.168.1.10' #neither works with list dhcp_option

config host
        option name 'myLaptop'
        option leasetime 'infinite'
        option ip '192.168.1.8'
        list mac 'F0:DD:DD:DD:DD:DD'
        list tag 'tag1'
8

Sure, here is my /etc/config/dhcp, hidden MACs, changed used subnet), for the test purpose I've removed all other leases.


root@router:~# cat /etc/config/dhcp

config dnsmasq
	option domainneeded '1'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option cachesize '1000'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
	option localservice '1'
	option ednspacket_max '1232'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '200'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'

config dhcp 'wan'
	option interface 'wan'
	option ignore '1'

config odhcpd 'odhcpd'
	option maindhcp '0'
	option leasefile '/tmp/hosts/odhcpd'
	option leasetrigger '/usr/sbin/odhcpd-update'
	option loglevel '4'

config myDNS 'tag1'
	option dhcp_option '6,192.168.1.10'

config host
	option name 'myDNSsrv'
	option leasetime 'infinite'
	option ip '192.168.1.10'
	option dns '1'
	list mac 'E0:DD:DD:DD:DD:DD'

config host
	option name 'myLaptop'
	option leasetime 'infinite'
	option ip '192.168.1.8'
	list mac 'F0:DD:DD:DD:DD:DD'
	list tag 'tag1'

config host
	option name 'AnotherDevice'
	option leasetime 'infinite'
	option ip '192.168.1.12'
	list mac 'D0:DD:DD:DD:DD:DD'
	list tag 'tag1'
root@router:~#

Client always receive router's IP as DNS, not my own DNS

Link 3 (wl...)
    Current Scopes: DNS
         Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.1.1
       DNS Servers: 192.168.1.1 fdaf:DDDD:DDDD::1
        DNS Domain: lan

The same in windows...

9

See the correct syntax.

If you want to name the tag section my_DNS, the config should look like this:

config tag 'my_DNS'
        option dhcp_option '6,192.168.1.10'

config host
        option name 'myLaptop'
        option leasetime 'infinite'
        option ip '192.168.2.8'
        list mac 'F0:DD:DD:DD:DD:DD'
        option tag 'my_DNS'
2 Likes
10

Seems works!

uci commands I used to create a TAG generated code as I shared.
Then I used LUCI to set the tag on existing leases.
Maybe here discrepancy appears?

When manually I've corrected syntax directly in /etc/config/dhcp as you suggested, everything started to work for tagged clients.

Thanks a lot, you and everyone who responded.
Appreciate!

1 Like
11

This topic was automatically closed 10 days after the last reply. New replies are no longer allowed.