On Linux machine ;
1- Edit file /etc/ssh/sshd_config and
* add 3des-cbc in the cipher list (if Ciphers parameter is set)
Example :
Ciphers aes256-ctr,aes192-ctr,aes128-ctr,aes256-gcm@openssh.com,aes128-gcm@openssh.com,chacha20-poly1305@openssh.com,3des-cbc
* add hmac-sha1 in the MACs list (if MACs parameter is set)
Example :
MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com,hmac-md5
* add diffie-hellman-group1-sha1 in the KexAlgorithms list (if KexAlgorithms parameter is set)
Example :
KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256,diffie-hellman-group1-sha1
2- Restart ssh server :
sudo systemctl stop sshd
sudo systemctl start sshd
On AIX Machine :
1- Edit file /etc/ssh/sshd_config (see above)
2- Restart ssh server
stopsrc -s sshd
startsrc -s sshd