Re: Is it really a HUB?

[Darryl Luff <dluff () iitscdm com au>]

Kristofer T. Karas wrote:

> Marc Quibell wrote:
>
> > > as long as one keeps one's box from transmitting
> > > any data, the hub/switch will not learn its MAC address, and should 
> > > send
> > > it everything.
> >
> > Actually, it will send it nothing at all....
>
> Thanks, but that doesn't really explain what is (or is not) going on.  
> In particular, it still leaves questions in my head as to the ability 
> of plugging several of these mini switches together to add ports.  
> Since they are not configurable as to network address

...
It works as you say. Except that if your station never transmits 
anything, the switch will not learn your MAC, and will flood all traffic 
addressed TO YOU out all ports. Traffic addressed to other MAC's will go 
through the bridging process you described, and so wont normally be seen 
by your station unless they're unknown MAC's, broadcasts, etc.

Switches can continue to operate in a LAN where the number of unique 
MAC's is larger than their forwarding table capacity. When new MAC's are 
discovered either older ones are dropped out of the table, or the 
complete table is cleared and learning starts again. So they will 
continue to operate, but there will be more packet flooding than 
necessary. And of course the forwarding table only needs enough capacity 
to hold the MAC's for the local LAN/VLAN, not the whole network.




-------------------------------------------------------
This SF.net email is sponsored by: SF.net Giveback Program.
Does SourceForge.net help you be more productive?  Does it
help you create better code?   SHARE THE LOVE, and help us help
YOU!  Click Here: http://sourceforge.net/donate/
_______________________________________________
Snort-users mailing list
Snort-users () lists sourceforge net
Go to this URL to change user options or unsubscribe:
https://lists.sourceforge.net/lists/listinfo/snort-users
Snort-users list archive:
http://www.geocrawler.com/redir-sf.php3?list=snort-users