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Bind9 Unit - Disable port 53 on the GLServer host

By EssingtonITS team ·

Issue

When running the GLServer bind 9 unit the unit fails to start due to a conflicting DNS port (53) Confirm port 53 is in use by the local DNSresolver service with the following command lsof -i :53 which will produce output similar to the following COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME systemd-r 1051 systemd-resolve 12u IPv4 25710 0t0 UDP localhost:domain systemd-r 1051 systemd-resolve 13u IPv4 25711 0t0 TCP localhost:domain (LISTEN)

Solution

Edit the following

/etc/systemd/resolved.conf

The file contents should replicate the following

[Resolve]
DNS=127.0.0.1
#FallbackDNS=
#Domains=
#LLMNR=no
#MulticastDNS=no
#DNSSEC=no
#Cache=yes
DNSStubListener=no

Create a sym link to the resolve.conf file

ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf

Restart the resolved service

systemctl daemon-reload
systemctl restart systemd-resolved.service

Test port 53 is no longer in use using the following command

lsof -i :53

If successful no output will be produced you can now restart the unit

gl -s bind9-unit-name

Managing modern applications across servers, networks, and environments can quickly become complex and costly.

EssingtonITS GL Server is a powerful platform designed to simplify the deployment and management of containerised application Units. Whether running a single server or a large multi-environment infrastructure, GL Server helps organisations deliver secure, scalable, and resilient services without requiring in-house DevOps expertise.

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