If you see message such as “debug1: Roaming not allowed by server
“, your system is affected by CVE-2016-0777 of OpenSSH.
Fix # 1
Use ssh client as follows:
$ ssh -v -o UseRoaming=no user@host
Fix #2 Update openssh server and client
Use your package manager to apply updates. For example on CentOS/RHEL one could run:
# yum update