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linuxnetwork-programmingiptables

Map ports on edge server to internal SSH services

I have a network.

There's an edge server with a public IP address.

There are multiple internal services 192.168.0.{1..255} with SSH running on port 22 that can be accessed via a private network from the edge server.

I have clients connecting from outside the network to the edge server on port range 30001-30255. I need to map these connections to internal SSH services like so:

  • ssh -p 30001 myedgeserver.com -> 192.6.0.1:22
  • ssh -p 30002 myedgeserver.com -> 192.6.0.2:22
  • ...
  • ssh -p 30255 myedgeserver.com -> 192.6.0.255:22

Can this be achieved with iptables?

Solution

  • Yes. You make a nat for each of the 255 ports. I am unaware that you can do it in one line. So 255 lines like this:

    iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 30001 -j DNAT \
  --to 192.6.0.1:22