icmp and port

icmp and port

[gis88530]

Hello,

I have study the code in ip_masq.c, and
I found that icmp packet use 
source address, destination address, source port and
destination port to hash into masquerade table.

Do icmp packets have port information?
I have print the port information with printk,
but I can't find out the answer to this question.
Could you give me a hint? Thanks a lot.

Cheers,
Tom

Re: icmp and port

[Andreas Ferber]

Hi,

On Tue, Apr 17, 2001 at 10:28:53PM +0800, gis88530 wrote:
> 
> Do icmp packets have port information?

ICMP packets quote part of the original packet that triggered the ICMP
message. From this quoted part, information can be extracted about the
connection the ICMP packet belongs to.

Andreas
-- 
I *____\b\b\b\bknew* I had some reason for not logging you off... If I could just
remember what it was.

Re: icmp and port

[gis88530]

Thanks for your answer, and I still have some questions.

(private)---->(masquerade)---->(public)
If I ping public host from private host using this command:
ping 140.113.1.1
What trigger ICMP message? The "ping" binary program?
AND
How masquerade gateway know the original packet port information?
Because I think original packets are in private hosts, masquerade
gateway can't get the original packet.

If I am wrong, please feel free to advice me.
Thanks in advance.

Cheers,
Tom
----- Original Message -----
From: "Andreas Ferber" <aferber@techfak.uni-bielefeld.de>
To: "gis88530" <gis88530@cis.nctu.edu.tw>
Cc: <linux-kernel@vger.kernel.org>
Sent: Tuesday, April 17, 2001 10:39 PM
Subject: Re: icmp and port


> Hi,
>
> On Tue, Apr 17, 2001 at 10:28:53PM +0800, gis88530 wrote:
> >
> > Do icmp packets have port information?
>
> ICMP packets quote part of the original packet that triggered the ICMP
> message. From this quoted part, information can be extracted about the
> connection the ICMP packet belongs to.
>
> Andreas
> --
> I *____\b\b\b\bknew* I had some reason for not logging you off... If I
could just
> remember what it was.
>
> -
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