Dnsmasq

dnsmasq provides LAN DNS caching, as well as static IPs for all your local machine names via their MAC addresses. It's perfect!

You don't even need systemd or to fiddle with wifi router, just let dnsmasq do it all. Fuck yeah.

Show leases

mh-watch-leases
# which does this: ssh -t bp watch -n 1 cat /var/lib/misc/dnsmasq.leases

Release leases

You have to stop, remove leases from the leases file, and restart dnsmasq:

sudo service dnsmasq stop && sudo emacs /var/lib/misc/dnsmasq.leases && sudo service dnsmasq start

Configuration

Main config is here:

bitpost:/etc/dnsmasq/mdm_lan_dnsmasq.conf

Provide LAN DHCP range:

# MDM LAN ubuntu interface
dhcp-range=enp5s0f1, ...

Provide WAN interface:

# MDM WAN interface: 10g Intel NIC
interface=enp10s0f1

Dnsmasq will be all we need for all DNS:

# Make clients that request IPs use this box for DNS
dhcp-option=option:router,192.168.22.1

Allow "single-label" (LAN name) DNS lookups (without a dot suffix):

# MDM We have to get systemd-resolved to allow "single-label" DNS lookups.
# This seems to do the trick.  Whew.
# https://askubuntu.com/questions/917784/systemd-resolved-does-not-query-dns-server-for-local-domain
# https://github.com/systemd/systemd/issues/13763
domain=bitpost.lan
local=/bitpost.lan/
expand-hosts

Provide upstream DNS right in the config file - relying on /etc/resolv.conf was a nightmare.

# MDM add upstream cloudflare DNS servers here, as /etc/resolv.conf isn't working and is constantly fucked with!
# This gets the job done so that the entire LAN can go through bitpost DNS to get to cloudflare DNS.  Yes!
server=1.1.1.1
server=1.0.0.1

Finally... the LAN static IPs...

#=========================================================================================================
# MDM MY STATIC IPs!  Sync with /etc/hosts on bitpost!  Everything that uses bitpost for DHCP will work!
# To see what has been given a dhcp lease: bitpost ~ # cat /var/lib/misc/dnsmasq.leases
#=========================================================================================================
dhcp-host=(MAC),bitpost,(IP)           # main router/abt server; aka [bp]
dhcp-host=(MAC),case,(IP)              # wired 319 living room kodi + backup gaming rig
(etc.)

Adding a new host

Add a new line to the config file with an available IP, and host and MAC of the new box.

Windows DNS resolution

Windows apparently puts a suffix on names, unless you end them with a dot, so sometimes in Windows you have to use something like this:

 \\hive.\reservoir

Disable systemd-resolved

NOTE this totally replaces systemd-resolved THANK the lord - disable that shit! systemctl disable systemd-resolved.service systemctl stop systemd-resolved.service

MDM not sure this is needed- i'd like to remove resolv.conf entirely... there is a way but i'll wait until i'm home to try it...

rm /etc/resolv.conf ln -s /run/resolvconf/resolv.conf /etc/resolv.conf

this will remove the resolved stub resolver entry from resolv.conf

resolvconf -d systemd-resolved