When I try to clone a github repo, I get the error above.
$ ssh -vvv firstname.lastname@example.org OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g 1 Mar 2016 [snip] debug2: resolve_addr: could not resolve name github.com as address: Name or service not known ssh: Could not resolve host "github.com"
Using HTTPS instead works fine. Accessing github via any non-SSH method works fine:
$ ping github.com PING github.com (18.104.22.168) 56(84) bytes of data. 64 bytes from 22.214.171.124: icmp_seq=1 ttl=44 time=109 ms
SSH to a number of other domains works fine.
After some googling I found out about
getent which gives me
$ getent hosts github.com fe80::4cdd:72ff:fe74:ae1 github.com.myhotspot.lan
so I guess the router is hijacking things somehow but my linux fu is not strong enough to figure out how to test or fix that.