Written by akendo on 
2 minutes reading posted in Linux
with tags: archlinux systemd

Issue resolving locale hostnames

Since some days one of my laptop has the problem to resolve certain hostnames. All hostnames that are without any type TLD like git or gw. The thing is, that the FQDN resolution remained working for the same hosts. Lucky, I have two laptop that did not had the same behaviour but with similar configuration. Running ping on the first device fails, while the second once succeeds:

One the first laptop is does not work:

ping git -c1
ping: git: Name or service not know

On my other device the same command is running flawless:

ping git -c1
PING git (172.X.Y.Z) 56(84) bytes of data.
64 bytes from 172.X.Y.Z (172.X.Y.Z): icmp_seq=1 ttl=64 time=1.06 ms

--- git ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.055/1.055/1.055/0.000 ms

So what might cause the divergent? After some ideas developed I found a interesting differents: Laptop one has systemd-resolved enabled, the other not:

● systemd-resolved.service - Network Name Resolution
     Loaded: loaded (/usr/lib/systemd/system/systemd-resolved.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2020-07-02 19:32:51 CEST; 15h ago
       Docs: man:systemd-resolved.service(8)
             https://www.freedesktop.org/wiki/Software/systemd/resolved
             https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
             https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients
   Main PID: 1204 (systemd-resolve)
     Status: "Processing requests..."
      Tasks: 1 (limit: 18905)
     Memory: 13.6M
     CGroup: /system.slice/systemd-resolved.service
             └─1204 /usr/lib/systemd/systemd-resolved

While the other devices does not have it active:

● systemd-resolved.service - Network Name Resolution
     Loaded: loaded (/usr/lib/systemd/system/systemd-resolved.service; disabled; vendor preset: enabled)
     Active: inactive (dead)
       Docs: man:systemd-resolved.service(8)
             https://www.freedesktop.org/wiki/Software/systemd/resolved
             https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
             https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients

Disabling the service solve it! The issue was in fact the systemd-resolverd.

sudo systemctl stop systemd-resolved.service
ping git -c1
PING git (172.X.Y.Z) 56(84) bytes of data.
64 bytes from 172.X.Y.Z (172.X.Y.Z): icmp_seq=1 ttl=64 time=1.06 ms

--- git ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.055/1.055/1.055/0.000 ms

The core question is now: What’s the issue that systemd-resolved does not resolve the locale host and why was is active on the first device but no other? But this is a question I might answer another time.

best regards

Sources:

tags: Archlinux, systemd