Receive UDP packets not destined to me

[Wim Van den Wyngaert]

Why is my node receiving UDP packets not sent to my node (not even my network) ?

Wim

[John Abbott_2]

Hi Wim, point 3 from this think might explain the reason.

http://www.comptechdoc.org/independent/networking/guide/netbroadcasting.html

Must dash !

[Ian Miller.]

I see from http://www.911networks.com//pages/internet/firewall/bogus-ip-addresses-class-a.php

65.255.255.255 is a bogus address. I wonder if it was sent to a broadcast ethernet address.

[Wim Van den Wyngaert]

Yes it is sent as a broadcast. So all 65 addresses should receive it. But mine is a 128. So why is it listening for 65 packets.

Ian : misused addresses must be refused by the firewall. But that doesn't say that it is considered as a special address where all nodes are listening to.

WIm

[Walter Miller_1]

Do you have BOOTP enabled on this node? This could be a bootp request possibly related to your http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=994380 thread.

[Wim Van den Wyngaert]

Bootp sends a broadcast to all nodes (except when it is already in 65.0.0.0 then it is to 65.*).
But why is my node listening to something not addressed to him ?

Wim

[Walter Miller_1]

A BOOTP request broadcasts to UDP port 67. My understanding is that a BOOTP server must evaluate any request to UDP port 67 regardless of the TCPIP address/mask. Of course the server must be on the same segment as the requesting device the same as a MOP request.

[Wim Van den Wyngaert]

Walter,

Can you make that hard ? I don't find any of that in the RFC http://www.networksorcery.com/enp/default0501.htm.

As I understand it, BOOTP listens to a port and IP filters based upon the destination address. So, if the destination is 255.255.255.255 it will pass, if it is 65.255.255.255 it will pass if the receiver is in 65, which in my case isn't.

Wim