Failed to Add a Target Environment on the Java Profiler

Symptom

Failed to add a target environment on the Java Profiler.

Possible Causes

• The time when the certificate takes effect is later than the current system time.
• The SSH security configuration does not meet software requirements.

Troubleshooting Procedure

If the system time is incorrect, correct it and add a target environment again.

If the SSH security configuration is incorrect, perform the following steps:

1. Check whether MACs supports related algorithms.

   Check the sshd_config file in /etc/ssh.

   Figure 1 sshd_config file
   

   You can run the ssh -Q mac command to check whether hmac-sha2-256, hmac-sha2-256-etm@openssh.com, hmac-md5, hmac-sha1, umac-64@openssh.com, and hmac-ripemd160 are supported.

   Figure 2 Algorithms supported by MACs
   

   If the preceding algorithms are supported but not configured, add them to the sshd_config configuration file in the /etc/ssh directory (add only the algorithms that are supported):

   1	MACs hmac-sha2-256,hmac-sha2-256-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160

2. Check whether HostKey supports related algorithms.

   Check whether ssh_host_ecdsa_key and ssh_host_ed25519_key exist in /etc/ssh.

   Figure 3 Host keys
   

   If not, run the following commands to generate the corresponding host keys:

   1 2	ssh-keygen -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_key

   Uncomment the following content in or add the following content to sshd_config in the /etc/ssh directory:

   1 2	HostKey /etc/ssh/ssh_host_ecdsa_key HostKey /etc/ssh/ssh_host_ed25519_key

3. Check whether HostKeyAlgorithms supports related algorithms.
   1. Check whether HostKeyAlgorithms is configured. If not, skip this step. If yes, check whether ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521, ssh-ed25519, ssh-ed25519-cert-v01@openssh.com, or rsa-sha2-256 or rsa-sha2-512 exists in the include list.
   2. If none of the preceding algorithms exist, run the ssh -Q HostKeyAlgorithms command to view the list of supported encryption algorithms.
      Figure 4 Algorithms supported by HostKeyAlgorithms
      
   3. Select any algorithm in both the include list and the supported list and add it to the sshd_config file in the /etc/ssh directory.

      1	HostKeyAlgorithms ssh-ed25519,ssh-ed25519-cert-v01@openssh.com

4. Check whether Ciphers supports related algorithms.

   Run the ssh -Q cipher command to check the supported SSH symmetric keys.

   Figure 5 Algorithms supported by Ciphers
   

   If the preceding algorithms are supported but not configured, add them to the sshd_config configuration file in the /etc/ssh directory (add only the algorithms that are supported):

   1	Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc

5. Check the /etc/ssh/ssh_config file.
   Check whether the /etc/ssh/ssh_config file contains the following content. If not, add the content to the file.

   1	GSSAPIAuthentication yes

6. Restart the SSH service for the modification to take effect.

   1	systemctl restart sshd.service