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Re: rfc1978 help

  • From: Jeroen Massar
  • Date: Fri Nov 05 13:34:32 2004 
On Sat, 2004-11-06 at 02:07 +0800, adrian kok wrote:
> Hi all
> 
> Sth I want to clarify:
> 
> 1/ 
> 240.0.0.0/5         - Class E Reserved
> 248.0.0.0/5         - Unallocated
> Sometimes I got it should /4 or /5 ?
> 240.0.0.0/4       - Class E Reserved
> 248.0.0.0/4         - Unallocated

Look at the official list(tm):
http://www.iana.org/assignments/ipv4-address-space

> 2/ Can I block it in the firewall for
> "255.255.255.255/32  - Broadcast"?
> 
> deny ip from any to 255.255.255.255/32
> deny ip from 255.255.255.255/32 to any

You can block anything you like

> 3/ I got the following. ls it normail?
> why there is connection to the broadcast address
> 
> tcp        0      1 202.64.230.8:33397    
> 192.168.255.255:25      SYN_SENT

255.255 or anything ending in 255 doesn't need to be a broadcast
interface. Welcome to the wonderful world of CIDR :)

I guess you might want to take a look at:
http://www.cymru.com/Bogons/index.html

Greets,
 Jeroen

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