PUBLIC MARKS with tags firewall & ssh

Access your secure shell server by use of this free browser-based web SSH client. No more firewall or proxy restrictions for server and system administrators.

SSH has numerous uses beyond just logging into a remote system. In particular, SSH allows you to forward ports from one machine to another, tunnelling traffic through the secure SSH connection. This provides a convenient means of accessing a service hosted behind a firewall, or one blocked by an outgoing firewall. However, forwarding an individual port still requires you to change where your program connects, telling it to use a non-standard port on localhost rather than the standard port on the remote machine, and it requires a separate port forward for each machine you want to access. Dynamic port forwarding via SOCKS provides a more convenient alternative. The examples in this article assume that you reside behind a restrictive firewall which does not allow outgoing SMTP connections except to a designated mail server. You want to connect to a different mail server, mail.example.net, on port 25. You have an SSH account on a machine shell.example.org, which does not reside within the restrictive firewall and can thus access port 25 on mail.example.net.

regle IpTables pour bloquer les attaques par dictionnaire sur un port (par exemple le port SSH)

a plus de 4 tentatives de connexions en moins d'une minute, on bloque l'ip pendant une minute.

"port knocking is a method of externally opening ports on a firewall by generating a connection attempt on a set of prespecified closed ports"