Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.os.linux.networking > #4820
| From | "Carlos E.R." <robin_listas@es.invalid> |
|---|---|
| Newsgroups | comp.os.linux.networking |
| Subject | Re: Forwarding a TCP connection |
| Date | 2021-03-14 23:26 +0100 |
| Message-ID | <a5f2ih-eu3.ln1@Telcontar.valinor> (permalink) |
| References | <s2lqd7$1ljv$1@gioia.aioe.org> <phc2ih-jjv.ln1@Telcontar.valinor> <87czw1v1g0.fsf@LkoBDZeT.terraraq.uk> |
On 14/03/2021 23.02, Richard Kettlewell wrote:
> "Carlos E.R." <robin_listas@es.invalid> writes:
>> On 14/03/2021 21.07, John Smith wrote:
>>> I have a Linux system A in my network where a TCP server is
>>> running at port P. The details of this server are irrelevant beyond the
>>> fact that it is a TCP server.
>>>
>>> What I would like to do is the following;
>>>
>>> I have another Linux system B in the same network. Would it be
>>> possible to configure B so that when be receives a TCP connection request
>>> on port B, the connection is silently and transparently forwarded to A?
>>> That is, my goal is for B to act as man-in-the-middle, totally
>>> transparent as far as B is concerned.
>>>
>>> Can this be done?
>
> I used to use the iptables DNAT and SNAT targets to achieve this.
>
>> Certainly.
>>
>> For example, with an ssh tunnel, run on B:
>>
>> ssh -L 127.0.0.01:60000:192.168.1.16:80 -N user@A.mylan
>>
>>
>> A is on 192.168.1.16 in the example.
>
> With this approach, the server on A will see the wrong source address,
> not very transparent.
You can change the options as needed. I basically pasted what I use.
-L [bind_address:]port:host:hostport
-L [bind_address:]port:remote_socket
-L local_socket:host:hostport
-L local_socket:remote_socket
Specifies that connections to the given TCP port
or Unix socket on the local (client) host are to
be forwarded to the given host and port, or Unix
socket, on the remote side. This works by allo-
cating a socket to listen to either a TCP port
on the local side, optionally bound to the spec-
ified bind_address, or to a Unix socket. When-
ever a connection is made to the local port or
socket, the connection is forwarded over the
secure channel, and a connection is made to
either host port hostport, or the Unix socket
remote_socket, from the remote machine.
Port forwardings can also be specified in the
configuration file. Only the superuser can for-
ward privileged ports. IPv6 addresses can be
specified by enclosing the address in square
brackets.
By default, the local port is bound in accor-
dance with the GatewayPorts setting. However,
an explicit bind_address may be used to bind the
connection to a specific address. The
bind_address of “localhost” indicates that the
listening port be bound for local use only,
while an empty address or ‘*’ indicates that the
port should be available from all interfaces.
--
Cheers, Carlos.
Back to comp.os.linux.networking | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Forwarding a TCP connection John Smith <12345@whatismyemailaddress.xyz> - 2021-03-14 20:07 +0000
Re: Forwarding a TCP connection "Carlos E.R." <robin_listas@es.invalid> - 2021-03-14 22:41 +0100
Re: Forwarding a TCP connection Richard Kettlewell <invalid@invalid.invalid> - 2021-03-14 22:02 +0000
Re: Forwarding a TCP connection "Carlos E.R." <robin_listas@es.invalid> - 2021-03-14 23:26 +0100
Re: Forwarding a TCP connection Richard Kettlewell <invalid@invalid.invalid> - 2021-03-14 22:46 +0000
Re: Forwarding a TCP connection Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-03-15 09:42 +0100
Re: Forwarding a TCP connection Jim Jackson <jj@franjam.org.uk> - 2021-03-14 22:03 +0000
Re: Forwarding a TCP connection "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2021-03-14 17:40 -0400
Re: Forwarding a TCP connection John Smith <12345@whatismyemailaddress.xyz> - 2021-03-14 23:23 +0000
Re: Forwarding a TCP connection dyrmak <dyrmak@quelite.terre.invalid> - 2021-03-15 17:49 +0000
Re: Forwarding a TCP connection Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-15 20:14 +0200
Re: Forwarding a TCP connection "Carlos E.R." <robin_listas@es.invalid> - 2021-03-15 23:28 +0100
Re: Forwarding a TCP connection Jorgen Grahn <grahn+nntp@snipabacken.se> - 2021-03-15 23:15 +0000
Re: Forwarding a TCP connection dyrmak <dyrmak@orange.fr.invalid> - 2021-03-16 07:59 +0000
Re: Forwarding a TCP connection Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-16 11:16 +0200
Re: Forwarding a TCP connection Jim Jackson <jj@franjam.org.uk> - 2021-03-16 14:53 +0000
Re: Forwarding a TCP connection "Carlos E.R." <robin_listas@es.invalid> - 2021-03-16 03:21 +0100
Re: Forwarding a TCP connection Jim Jackson <jj@franjam.org.uk> - 2021-03-16 14:49 +0000
Re: Forwarding a TCP connection Johann Beretta <beretta@nun-ya-bizness.com> - 2021-05-28 13:19 -0700
Re: Forwarding a TCP connection Grant Taylor <gtaylor@tnetconsulting.net> - 2021-05-28 16:20 -0600
Re: Forwarding a TCP connection Johann Beretta <beretta@nun-ya-bizness.com> - 2021-05-28 13:15 -0700
Re: Forwarding a TCP connection Grant Taylor <gtaylor@tnetconsulting.net> - 2021-05-28 16:23 -0600
Re: Forwarding a TCP connection Marc Haber <mh+usenetspam1118@zugschl.us> - 2021-05-29 18:42 +0200
Re: Forwarding a TCP connection Grant Taylor <gtaylor@tnetconsulting.net> - 2021-05-29 19:29 -0600
Re: Forwarding a TCP connection Marc Haber <mh+usenetspam1118@zugschl.us> - 2021-05-30 12:08 +0200
Re: Forwarding a TCP connection Grant Taylor <gtaylor@tnetconsulting.net> - 2021-05-31 22:43 -0600
Re: Forwarding a TCP connection Marc Haber <mh+usenetspam1118@zugschl.us> - 2021-06-01 08:51 +0200
Re: Forwarding a TCP connection Johann Beretta <beretta@nun-ya-bizness.com> - 2021-03-24 19:30 -0700
Re: Forwarding a TCP connection Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-25 16:35 +0200
Re: Forwarding a TCP connection Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-03-25 20:03 +0100
Re: Forwarding a TCP connection Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-25 21:34 +0200
Re: Forwarding a TCP connection Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-03-25 21:54 +0100
Re: Forwarding a TCP connection Johann Beretta <beretta@nun-ya-bizness.com> - 2021-03-29 13:45 -0700
Re: Forwarding a TCP connection Johann Beretta <beretta@nun-ya-bizness.com> - 2021-03-29 13:43 -0700
Re: Forwarding a TCP connection Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-30 20:26 +0300
Re: Forwarding a TCP connection Johann Beretta <beretta@nun-ya-bizness.com> - 2021-03-30 22:49 -0700
Re: Forwarding a TCP connection Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-03-31 16:29 +0000
Re: Forwarding a TCP connection John Smith <12345@whatismyemailaddress.xyz> - 2021-03-14 23:13 +0000
Re: Forwarding a TCP connection Jorgen Grahn <grahn+nntp@snipabacken.se> - 2021-03-15 06:59 +0000
Re: Forwarding a TCP connection Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-03-15 09:48 +0100
Re: Forwarding a TCP connection John Smith <12345@whatismyemailaddress.xyz> - 2021-03-15 13:44 +0000
Re: Forwarding a TCP connection Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-03-15 20:49 +0100
Re: Forwarding a TCP connection John Smith <12345@whatismyemailaddress.xyz> - 2021-03-15 21:10 +0000
csiph-web