Where to look if X11 forwarding does not work

1. In /etc/ssh/sshd_config should be the options:

AddressFamily inet (if the host is ipv4 only)

X11Forwarding yes

2. in /etc/hosts shold be

127.0.0.1 localhost (if the host is ipv4 only)

3. try debugging ssh session:

/usr/sbin/sshd -d -p 222

4. DISPLAY environment variable should be set up by default after connecting to the ssh server.