Java Process Info Command

Java Process Info - Command

Command to list PID and Working Directory for Java processes

jps | grep -v Jps | while read pid _; do pwdx $pid; done

SSH Configuration for Connection Timeout and Security Settings

SSH Server Configuration (`/etc/ssh/sshd_config`)

The following settings help manage timeouts, session limits, and authentication attempts for SSH connections:

Configuration Settings:

Key Exchange Algorithms:
```
KexAlgorithms -diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1
```
- This configuration disables certain key exchange algorithms (diffie-hellman-group1-sha1, diffie-hellman-group14-sha1, and diffie-hellman-group-exchange-sha1).
- It is used to enforce stronger encryption algorithms and prevent weak ones.
Max Startups:
```
MaxStartups 10:30:60
```
- Controls the maximum number of simultaneous unauthenticated connections to the SSH server.
- 10: Maximum number of unauthenticated connections.
- 30: Percentage of connections rejected once the limit is reached.
- 60: The maximum number of unauthenticated connections after which the server blocks new ones.
Max Sessions:
```
MaxSessions 10
```
- Limits the number of open sessions per connection.
- In this case, a maximum of 10 sessions can be opened per SSH connection.
Max Authentication Tries:
```
MaxAuthTries 4
```
- Limits the number of authentication attempts allowed before disconnecting the client.
- After 4 failed attempts, the server disconnects the client.
Login Grace Time:
```
LoginGraceTime 60
```
- Specifies the time allowed for a client to authenticate after connecting.
- The client has 60 seconds to authenticate before the connection is closed.
Client Alive Interval:
```
ClientAliveInterval 300
```
- Controls how often the server sends a "keep-alive" message to the client to prevent disconnection due to inactivity.
- The server will send a message every 300 seconds (5 minutes).
Client Alive Count Max:
```
ClientAliveCountMax 1
```
- Specifies how many "keep-alive" messages can be missed before the server disconnects the client.
- With a value of 1, the server will disconnect the client if one "keep-alive" message is missed.

Recommended Adjustments for Longer Inactivity Period:

To allow a longer idle period before disconnecting:

ClientAliveInterval 600  # 10 minutes
ClientAliveCountMax 3    # Allow up to 3 missed messages before disconnecting

Apply Changes:

After modifying the sshd_config file, restart the SSH service to apply the changes:
```
sudo systemctl restart sshd
```

By adjusting these settings, you can control connection timeouts, improve security, and manage idle time more effectively.

Written by A.M. Rinas