“ssh_host_*_key” is 600.

# ls -lh /etc/ssh/ssh_host_*
-rw-------. 1 root root  668 Feb 23 18:35 /etc/ssh/ssh_host_dsa_key
-rw-r--r--. 1 root root  590 Feb 23 18:35 /etc/ssh/ssh_host_dsa_key.pub
-rw-------. 1 root root  963 Feb 23 18:35 /etc/ssh/ssh_host_key
-rw-r--r--. 1 root root  627 Feb 23 18:35 /etc/ssh/ssh_host_key.pub
-rw-------. 1 root root 1.7K Feb 23 18:35 /etc/ssh/ssh_host_rsa_key
-rw-r--r--. 1 root root  382 Feb 23 18:35 /etc/ssh/ssh_host_rsa_key.pub
#

copy /etc/ssh/ssh_host_* from old server to new server for VIP access with Act/Std, for server replace

• for VIP access with Act/Std
• for Server replace

# ssh  old-server ls -l /etc/ssh/ssh_host*
# scp -p old-server:/tmp/ssh_host* /tmp/

# ls -l /etc/ssh/ssh_host*
# mkdir /tmp/ssh_host_org/
# cp -p /etc/ssh/ssh_host* /tmp/ssh_host_org/
# cp -p /tmp/ssh_host* /etc/ssh/
# ls -lh /etc/ssh/ssh_host*
# systemctl restart sshd        <- [Old Linux] /etc/init.d/sshd restart