From: Charles Forsyth <forsyth@terzarima.net>
To: nikils@gmail.com, 9fans@cse.psu.edu
Subject: Re: [9fans] ip masquerading
Date: Wed, 8 Sep 2004 11:23:08 +0100 [thread overview]
Message-ID: <ff9058bbffc1730209802b3b25ea0ea7@terzarima.net> (raw)
In-Reply-To: <de0199910409080308331204f2@mail.gmail.com>
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it goes back to the port that sent it, which is always on the gateway
machine, which corresponds to a file in /net/icmp/ on the gateway
but if another node has imported that, and that node did the ping,
it's something like this:
node imports /net from gateway (import(4) dials exportfs(4) service on gateway)
gateway starts a gateway.exportfs serving 9P
...
node opens imported /net/icmp/clone
9P:
Topen -> gateway.exportfs
exportfs opens appropriate file on gateway
Ropen <- gateway.exportfs
node writes to the opened file
Twrite -> gateway.exportfs
gateway.exportfs does the write to the file on gateway
gateway.IPstack -> ICMP packet on net on port P
Rwrite <- gateway.exportfs
gateway.IPstack <- ICMP responses, queued for port P's file
...
node reads opened file
Tread -> gateway.exportfs
gateway.exportfs does the read of file on gateway
Rread <- gateway.exportfs (with data for port P's file)
...
where the T- and R-messages are 9P messages on the channel set up by import(4) between
node and the exportfs(4) on the gateway, assuming the gateway
provides that service (see listen(8)). the kernel doesn't do anything special,
which is indeed the point, so reading the kernel code wouldn't be particularly helpful.
man 4 import, man 4 exportfs, and man 3 ip would be more helpful.
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From: Nikhil S <nikils@gmail.com>
To: 9fans <9fans@cse.psu.edu>
Subject: Re: [9fans] ip masquerading
Date: Wed, 8 Sep 2004 15:38:38 +0530
Message-ID: <de0199910409080308331204f2@mail.gmail.com>
When you import gateway's outside ip stack as /net.alt and try to ping
/net.alt/<outside ipaddress> i can understand that the ping packet is
sent from gateway's outside ip stack using its outside ipaddress etc.
what happens when the ping response comes back. will that packet be
forwarded to both gateway and inside machine ? or only to inside
machine ?
how does this internally work. i mean when you import /net.alt the
ippacket with header is forwarded or without header ?
i havent seen kernel code. just curious
next prev parent reply other threads:[~2004-09-08 10:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-08 6:44 Nikhil S
2004-09-08 8:49 ` geoff
[not found] ` <497b48e52d028c9cd68b5283a6a78927@collyer.net>
2004-09-08 9:10 ` Nikhil S
2004-09-08 9:14 ` geoff
2004-09-08 9:34 ` Charles Forsyth
[not found] ` <10978f9511a2be00107237fc8117c104@terzarima.net>
2004-09-08 10:08 ` Nikhil S
2004-09-08 10:23 ` Charles Forsyth [this message]
2004-09-08 12:59 ` Russ Cox
2004-09-08 9:17 bmaroshe
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