Could not resolve host, but the IP address works

Likely causes

1. No nameserver line in /etc/resolv.conf.
2. A nameserver that is down, unreachable, or refuses your network.

Diagnose

Run these in order. The output is what each printed on a lab's real Linux machines.

laptop:~# curl -sS -m 5 http://webServer.lab/

The name fails: Could not resolve host. curl never tried to connect.

curl: (6) Could not resolve host: webServer.lab

laptop:~# ping -c1 -W1 10.0.2.10

The same server by address answers, so the network is fine and only names are broken.

PING 10.0.2.10 (10.0.2.10) 56(84) bytes of data.
64 bytes from 10.0.2.10: icmp_seq=1 ttl=63 time=0.154 ms

--- 10.0.2.10 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.154/0.154/0.154/0.000 ms

Fix

/etc/resolv.conf on laptop

One line names the DNS server: here the router, 10.0.1.2.

nameserver 10.0.1.2

laptop:~# curl -sS -m 5 http://webServer.lab/

The page loads by name.

hello from webServer

Break it and fix it yourself

Each lab is a small network of real Linux machines in your browser, where this fault happens.

• A bare machine: networking by hand Free: its challenge "Names that go nowhere" set the fault for you to find and fix.

Open A bare machine: networking by hand