how can I use iptables to forward (or redirect) traffic from one ip port to another specific IP port?

IcLod

6/14/24, 6:39 AM

The prerequisite is:

HostA: (can access public machine, can't access hostA and hostB)              CentOS 7
HostB: (private machine, I can login, and it can access hostA and hostC,  )   CentOS 7
HostC: (private machine, svn server， IP:)

I need to hostA to "svn co http://hostC_IP:port/svn_repository".

And I set a "screen -dmS svn ssh -R HostAPublicIP:11002:HostC_IP:80 user@HostA_PublicIP -p2222" on hostB that the hostA can checkout the svn by " svn co http://127.0.0.1:11002/svn_repository". It works well.

But there is another problem that the svn repository has external links and the HostA can't checkout the external repository( the external repository's address is the same HostC_IP). So I thought of a method: use the "ip forward" to solve it.

The detail is that use the original address to checkout,and the "HostC_IP:80" forward to "127.0.0.1:11002" through the ssh tunnel:

sudo sysctl -w net.ipv4.conf.all.route_localnet=1
sudo iptables -t nat -A POSTROUTING -p tcp -d HostC_IP --dport 80 -j SNAT --to-source 127.0.0.1
# /proc/sys/net/ipv4/ip_forward=1   has setted

It didn't work.

What can I do to make it run properly or is it impossible?

1 + 0

iptables

ssh-tunnel

centos7

Score:0

Server

VSYS Host

7/6/24, 9:36 AM

It is very hard to understand your question, but if take a look at mentioned rule, it looks like you need to use -DNAT --to-dest

+ 0

Elon Musk

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EN: how can I use iptables to forward (or redirect) traffic from one ip port to another specific IP port?

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