![ssh proxy to protect old ssh servers ssh proxy to protect old ssh servers](https://globalssh.us/wp-content/uploads/2020/10/image-2.png)
Some local area networks (LANs) have their own internal domain name service to assign its own host names.
![ssh proxy to protect old ssh servers ssh proxy to protect old ssh servers](https://i.ytimg.com/vi/uUZ_seviwJY/hqdefault.jpg)
Using Canonical Host Names Which Are Behind Jump Hosts Of course the tests will have to be more complicated if the client machine moves between several different networks with the same numbering. But if there is a direct connection the client will proceed without the jump host. Likewise it would also send all connections to the network 192.168.2.* through the second jump host if there is no direct connection. That would catch all connections going to the network 192.168.1.*, if there is no direct connection, and send them through the first jump host. Match host 192.168.2.* !host !exec "nc -z -w 1 %h %p" ProxyJump Match host 192.168.1.* !host !exec "nc -z -w 1 %h %p" ProxyJump The second case is for occasions when the target machines are on another network.
![ssh proxy to protect old ssh servers ssh proxy to protect old ssh servers](https://i.stack.imgur.com/RkIjU.png)
The first example is for occasions when there is no local IPv6 connectivity when connecting to a remote machine which has only IPv6.
Ssh proxy to protect old ssh servers how to#
Below are two cases for how to automatically choose when to use ProxyJump to connect via an intermediate host. It is possible to use Match exec to select for difficult patterns or otherwise make complex decisions, such as which network the client is connecting from or the network connectivity of the available network(s). For more on using the older Prox圜ommand directive see the section below, Prox圜ommand with Netcat.Ĭonditional Use of Jump Hosts Otherwise, the recommended way would have been to use ProxyJump. With those settings, it is then possible to connect to the host on the LAN via the jump host simply with the line ssh server and all the settings will be taken into use. Prox圜ommand ssh jump route -T 1 exec nc %h %p When port forwarding is available the easiest way is to use ProxyJump in the configuration file or -J as a run-time parameter. The outdated netcat method does not allow a change of username. Attention must also be paid to whether or not the username changes from host to host in the chain of SSH connections. The SSH protocol is forwarded by nc instead of ssh. Using the Prox圜ommand option to invoke Netcat as the last in the chain is a variation of this for very old clients. But this method cannot be used if the intermediate hosts deny port forwarding. So the traffic passing through the intermediate hosts is always encrypted. In addition to whatever other encryption goes on, the end points of the chain encrypt and decrypt each other's traffic. This is the most secure method because encryption is end-to-end. The main method is to use an SSH connection to forward the SSH protocol through one or more jump hosts, using the ProxyJump directive, to an SSH server running on the target destination host. It is possible to connect to another host via one or more intermediaries so that the client can act as if the connection were direct.
![ssh proxy to protect old ssh servers ssh proxy to protect old ssh servers](https://globalssh.us/wp-content/uploads/2020/10/image-4.png)
Jump Hosts - Passing Through a Gateway or Two 5 Passing Through a Gateway with an Ad Hoc VPN.4.1 Tunneling the SSH Client Over Tor with Netcat.3.1 Old: SOCKS Proxy Via a Single Intermediate Host.2.1 Old: Port Forwarding Via a Single Intermediate Host Without ProxyJump.2 Port Forwarding Through One or More Intermediate Hosts.1.5.2.1 Old: Prox圜ommand without Netcat, Using Bash's /dev/tcp/ Pseudo-device.1.5.1.2 Old: Recursively Chaining an Arbitrary Number of Hosts.1.5.1.1 Old: Recursively Chaining Gateways Using stdio Forwarding.1.5.1 Old: Passing Through a Gateway Using stdio Forwarding (Netcat Mode).1.5 Old Methods of Passing Through Jump Hosts.1.4 Using Canonical Host Names Which Are Behind Jump Hosts.1.2 Transiting a Jump Host Which Has Multiple RDomains / Routing Tables.1.1 Passing Through One or More Gateways Using ProxyJump.1 Jump Hosts - Passing Through a Gateway or Two.