How to query whether SSH is available under Debian?

Question

I'm trying to implement ssh server under a custom Debian-based installation, which has no GUI, and yet no ssh access. How can I know whether SSH is installed, and how can I know whether the firewall actually allows it or not ?

Answer 1

To check whether the firewall allows it (assuming you're using iptables) write iptables -l (with root, otherwise put sudo in front).

As to whether the ssh-server is installed or not (assuming you're using packages) do aptitude search openssh-server and check the status marker next to the name.

If you're outside the server, simply try to connect to the IP on port 22 to verify/check that it is open :)

Answer 2

Ask the server administrator ;)

Otherwise it just seems shady with the details you've given us.

Answer 3

1. If you have console access, dpkg -l openssh-server will tell you whether or not the SSH server package is installed.
2. Running pgrep sshd will return the process ID of the SSH daemon if it is running.