Re: what's 224.0.0.0 -- and other newbie net-questions

[Robert Heine <heine@lionradio.de>]

Will Trillich <will@serensoft.com> writes:


> On my `ipfwadm -leO` output i notice among other rules...
> 
> IP firewall output rules, default policy: deny
>  pkts bytes type  prot opt  tosa tosx source     destination  ports
>     0     0 acc   udp  ---- 0xFF 0x00 0.0.0.0/0  224.0.0.0/4  * -> *
>     0     0 acc   icmp ---- 0xFF 0x00 0.0.0.0/0  224.0.0.0/4  *
> [columns omitted for space]
> 
> this is something that appeared after an 'apt-get upgrade'
> (currently in frozen with a slink kernel).
> Q: what's the 224.0.0.0 ip/netmask for?
> Q: what's the scheme behind ports '* -> *'?
> 
> With a netmask of /4 digits, the 224 (decimal) translates to
> 'E0' (hex); so valid values for the first 'dot' are anything
> from 224 (E0) to 239 (EF). I'm familiar with some reserved
> blocks of IP numbers, such as 168.192.*.* and 127.0.0.1 --
> so, what's (E*).*.*.* for?

Hi, 
AFAIK 224.0.0.0 is the adress for multicasting.
You can enable/disable this in the 2.2.x kernel

Regs
  Baer
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