Dnsmasq conflicts with systemd resolved

[shaozhai]

pi@rock3a:~$ sudo netstat -anlp | grep -w LISTEN
[sudo] password for pi:
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1445/sshd:

/usr/sbi
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1411/cupsd

tcp 0 0 127.0.0.1:6010 0.0.0.0:* LISTEN 3071/sshd:

pi@pts/1
tcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN

559/systemd-resolve
tcp6 0 0 :::22 :::* LISTEN 1445/sshd:

/usr/sbi
tcp6 0 0 ::1:631 :::* LISTEN 1411/cupsd

tcp6 0 0 ::1:6010 :::* LISTEN 3071/sshd:

pi@pts/1
pi@rock3a:~$

Selecting previously unselected package dnsmasq-base.
(Reading database ... 163545 files and directories currently installed.)
Preparing to unpack .../dnsmasq-base_2.84-1ubuntu2.1_arm64.deb ...
Unpacking dnsmasq-base (2.84-1ubuntu2.1) ...
Selecting previously unselected package dnsmasq.
Preparing to unpack .../dnsmasq_2.84-1ubuntu2.1_all.deb ...
Unpacking dnsmasq (2.84-1ubuntu2.1) ...
Selecting previously unselected package batctl.
Preparing to unpack .../batctl_2020.4-2_arm64.deb ...
Unpacking batctl (2020.4-2) ...
Setting up dnsmasq-base (2.84-1ubuntu2.1) ...
Setting up dnsmasq (2.84-1ubuntu2.1) ...
Created symlink /etc/systemd/system/multi-user.target.wants/dnsmasq.service →

/lib/systemd/system/dnsmasq.service.
Job for dnsmasq.service failed because the control process exited with error code.
See "systemctl status dnsmasq.service" and "journalctl -xe" for details.
invoke-rc.d: initscript dnsmasq, action "start" failed.
● dnsmasq.service - dnsmasq - A lightweight DHCP and caching DNS server
Loaded: loaded (/lib/systemd/system/dnsmasq.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2022-03-27 07:43:17 UTC; 45ms ago
Process: 3938 ExecStartPre=/etc/init.d/dnsmasq checkconfig (code=exited,

status=0/SUCCESS)
Process: 3943 ExecStart=/etc/init.d/dnsmasq systemd-exec (code=exited, status=2)

Mar 27 07:43:17 rock3a systemd[1]: Starting dnsmasq - A lightweight DHCP and caching DNS

server...
Mar 27 07:43:17 rock3a dnsmasq[3943]: dnsmasq: failed to create listening socket for port

53: Address already in use
Mar 27 07:43:17 rock3a dnsmasq[3943]: failed to create listening socket for port 53:

Address already in use
Mar 27 07:43:17 rock3a dnsmasq[3943]: FAILED to start up
Mar 27 07:43:17 rock3a systemd[1]: dnsmasq.service: Control process exited, code=exited,

status=2/INVALIDARGUMENT
Mar 27 07:43:17 rock3a systemd[1]: dnsmasq.service: Failed with result 'exit-code'.
Mar 27 07:43:17 rock3a systemd[1]: Failed to start dnsmasq - A lightweight DHCP and caching

DNS server.
Setting up batctl (2020.4-2) ...
Processing triggers for man-db (2.9.4-2) ...
Processing triggers for dbus (1.12.20-1ubuntu3) ...
pi@rock3a:/etc/mesh-micro$

[shaozhai]

I use the armbian system

[JonStratton]

I believe I fixed this issue in 24179f6 . Basically, dnsmasq was being used when when the node was in "server" mode so all client machines would be served IP addresses. This behavior was indented for just other devices on the batman-adv network with "interface=bat0" in the dnsmasq.comf file.

However, I noticed recently that a server was listening on all interfaces, not just on bat0. This appears to have been due to a missing "bind-interfaces" config. I dont know if this was previously not needed with earlier versions of dnsmasq, or if this has always been broken.

I believe this is also fixes the issue for #3 , as that issue appears to also be a conflict between DNSmasq and the systemd use of port 53. I will also be closing that down too. If I am wrong, please re-open and I will go out of my way to figure out whats going on.