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Re: packets with source ip 0.0.0.0

Subject: Re: packets with source ip 0.0.0.0
From: Moe Trin
Date: Tue, 03 May 2005 18:14:08 -0500
Newsgroups: comp.os.linux.networking
In article <42777b19$0$295$4d4eb98e@xxxxxxxxxxxxxxxxxxx>, Vincent Jaussaud
wrote:

>linux.lover2004@xxxxxxxxx wrote:

>>       I am working on linux and i observe that i am getting some
>> 0.0.0.0 packets? I want to know who is sending those packets? Are they
>> sent by services running on my Linux box?

>There is no reason why a process should ever send packet with src IP set to
>0.0.0.0

0.0.0.0 usually means "I don't know my address"  - as in

  2131 Dynamic Host Configuration Protocol. R. Droms. March 1997.
     (Format: TXT=113738 bytes) (Obsoletes RFC1541) (Updated by RFC3396)
     (Status: DRAFT STANDARD)

  3330 Special-Use IPv4 Addresses. IANA. September 2002. (Format:
     TXT=16200 bytes) (Status: INFORMATIONAL)

>Or some sort of security tools using a spoofed IP.

Hmmm, I've never tried that with nmap, but it's not possible to establish
a TCP connection if there is a router involved, as most routers will
silently discard packets to that address, unless they are a DHCP forwarder.

>You should tcpdump your interfaces to see where these packets are coming
>from, and track them hop by hop, up to the real source.

Really wouldn't expect them to be going beyond the router, but tcpdump
(or similar) is the key.

        Old guy


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