No DNS resolution. Even direct query to Google doesn't work.

LAN: 192.168.8.0/24 GW/DNS: 192.168.8.1

# nslookup google.com 8.8.8.8
Server:    8.8.8.8
Address 1: 8.8.8.8
 
nslookup: can't resolve 'google.com'

Router shows no new connection from host to port 53.

Strange is that, there is hanging UDP connection to port 53

# netstat -n
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0     64 192.168.8.107:22        192.168.8.106:4922      ESTABLISHED
udp        0      0 192.168.8.107:58218     192.168.8.1:53          ESTABLISHED

Which belongs to Oscam:

# netstat -n -W -p
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address                                       Foreign Address                                     State       PID/Program name
tcp        0     64 192.168.8.107:22                                    192.168.8.106:4922                                  ESTABLISHED 1912/dropbear
udp        0      0 192.168.8.107:58442                                 192.168.8.1:53                                      ESTABLISHED 1473/oscam