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Groups > comp.os.linux.networking > #4837

Re: Forwarding a TCP connection

From "Carlos E.R." <robin_listas@es.invalid>
Newsgroups comp.os.linux.networking
Subject Re: Forwarding a TCP connection
Date 2021-03-16 03:21 +0100
Message-ID <3ah5ih-l0b.ln1@Telcontar.valinor> (permalink)
References <s2lqd7$1ljv$1@gioia.aioe.org> <op.0z9k5pu0a3w0dxdave@hodgins.homeip.net> <slrns4v7h8.3f3.dyrmak@quelite.terre> <3l35ih-6mu.ln1@Telcontar.valinor> <slrns4vqkn.2ptb.grahn+nntp@frailea.sa.invalid>

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On 16/03/2021 00.15, Jorgen Grahn wrote:
> On Mon, 2021-03-15, Carlos E.R. wrote:
>> On 15/03/2021 18.49, dyrmak wrote:
>>> En 33 lignes David W. Hodgins a écrit
>>> dans news:op.0z9k5pu0a3w0dxdave@hodgins.homeip.net
>>>    le dimanche, 14 mars 2021 à 22:40:27 :
>>>
>>>>> 	Can this be done?
>>>>
>>>> It's called network address translation.
>>>>
>>>> iptables -t nat -A PREROUTING -p tcp --dport 2222 \
>>>>             -j DNAT --to-destination 1.2.3.4:8888
>>>>
>>>> Do you not control the router that's sending the packet to B in the first place?
>>>>
>>>> On my lan, the router forwards packets for some ports to one lan computer, and
>>>> packets for some other packets to another one.
>>>>
>>>> Or do you intend to have B do additional things with the packet, such as logging.
>>
>>>>
>>>    It seems to me that somehow A & B are directly connected to each
>>>    other through and eth cable or something, in a LAN all machines go
>>>    through the router and the router can send packets to another machine
>>>    with a set of simple rules, for this, checking out the router, if
>>>    any, might be a good idea.
>>
>> Home routers are not actually "routing" the LAN. The LAN is connected to
>> a switch in the "router" box. The router part of the "router" does not
>> intervene in that traffic.
> 
> And meanwhile, boxes called "managed switches" seem to be, amongst
> other things, routers.  Then if you pay a lot more, they are called
> "routers" again. The terminology is terribly confused.

Right :-)

Oh, and I forgot that the routing table of the computers in the LAN may 
be configured so that the send LAN traffic to the gateway (so that it 
does traverse the actual router). It is an error, of course, as it slows 
traffic, but I have seen it.


-- 
Cheers, Carlos.

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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

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