Wireshark-users: Re: [Wireshark-users] Router broken or is my Linux crazy? *Smallest* log include
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From: Stephen Fisher <stephentfisher@xxxxxxxxx>
Date: Mon, 10 Mar 2008 14:06:04 -0600
On Mon, Mar 10, 2008 at 06:56:15PM +0000, Monkey D. Luffy wrote:

> Still, I look at my current IP and the mask seems odd (although I 
> never did quite grasped the mask concept).
> inet addr:xxx.xxx.73.144  Bcast:xxx.xxx.73.255  Mask:255.255.252.0
> Shouldn't the mask's 3rd octet be 255?

If the third octet was 255, then the addresses available would be 
xxx.xxx.xxx.[1-254].  With the third octet 252 as you said above, the 
addresses available are xxx.xxx.[0-3].[1-255] as an example.  It could 
be any set of four 256 address blocks or 1024 addresses.  It's just a 
way to put more machines on the same subnet.

> And another strange thing shows in the log:
> 18 283.873122  192.168.2.100         239.255.67.250        IGMP     V2
> Membership Report
> 
> Why the heck does my computer want to communicate to that address?

That's a protocol that multicast uses to join multicast groups and 
239.255.67.250 is the group number.  Don't worry about it :)


Steve