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reverb - connection adapter
by team teso
1. motivation / description
ehm... imagine two cables that are both male (meaning that the pins look
out of it at the plug). imagine putting them together.
now imagine the same for both two female plugs of a cable, you will fail
also. what you need is a cable adapter with both female or male plugs.
the same is true for tcp connections (wow, what a parallelism, i'm cool,
am i ? :o)=, you can have active (male, yeah) and passive (female, :-)
ports, ehm... sockets hehe. normally a connection has one active (male)
and one passive (female) socket, and normally the male socket connects
into^H^H^H^Hto the female socket. but what if you want to create a link
between two sockets of the same type (male + male, female + female).
although this is only needed few times (irl this is more often i think ;),
it may be helpful. this is what reverb does.
2. usage
case a)
normal tcp connection relay, from sourceport to an ip and remote port.
reverb 2929 193.32.74.203:80
will relay one (1) connection experienced on port 2929 to the ip and
port specified.
case b)
accepting two connections relaying content.
reverb 2992 2991
will accept one (1) connection each on the ports and relay all content
between them. it doesn't matter (tm) what port the first connection is
established on.
case c)
establishing two connections, relaying content.
reverb 193.32.74.203:80 210.167.178.38:80
establishes two connections to each socketpair and relays the connection
data among them.
3. what for then ehm ?
you can reverse (reverb ;) a connection establishing order this way. this
is useful for a lot of things, such as firewall tunneling for internal
connections or whatever.
also you can see quickly what is send to a port, or you can link two char-
gen ports via tcp, hey cool ehh ?
conclusion: the ideal addition to tacten err.. netcat.
4. new options
times are given in formats like "10", "10s", "2m20s", "1d8h", ...
-c time
limits the connection timeout on every outgoing connection. once it is
reached, reverb terminates.
-l time
same for the female part, the listening socket.
-d
daemon mode, go to background. also causes quiet mode.
-q
quiet mode, don't print all that nasty infos.
-i time
for active<->active setups you can instance a new connection with it
every once a 'time'. for example you can use it to connect every five
minutes to a host outside a firewalled network to allow yourself to
ssh into the network from the outside
(./reverb -d -q -i 5m ownedhost-in-local-network:22 my-home-host:9090
on the owned host, and
./reverb -d -q -l 9090 2020;ssh -p 2020 root@localhost
on my-home-host).
visit us at teso.scene.at.
team teso
oh, and please send us feedback at teso@teso.scene.at.
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