From: J Finn <[EMAIL PROTECTED]>
   Date: Sun, 5 Jun 2005 20:26:42 -0400

   I've got a quick question I'm hoping someone can answer.

   If I've got a server with 3 interfaces on three different network, Is  
   there a portable way in perl to get the broadcast addresses of each  
   of those networks?

   for example, if I've got an ip address: 192.168.1.33 and the netmask  
   is 255.255.255.192 (range .32-.63), how can I find the broadcast  
   address (192.168.1.63)?

   Thanks

   -jf

Depends on what you mean by 'portable.'  I just pull the answer directly
from the output of ifconfig.  That is probably safest, as this may have
something different from the value you would compute:

    eth1      Link encap:Ethernet  HWaddr 00:90:27:BD:F2:6F  
              inet addr:24.34.108.24  Bcast:255.255.255.255  Mask:255.255.248.0
              inet6 addr: fe80::290:27ff:febd:f26f/64 Scope:Link
              UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:30307825 errors:0 dropped:0 overruns:0 frame:0
              TX packets:3937613 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:100 
              RX bytes:2770021884 (2641.6 Mb)  TX bytes:1617715374 (1542.7 Mb)
              Interrupt:11 Base address:0xd000 Memory:eb100000-eb100038 

The 'Bcast:' value in this case was supplied by the Comcast DHCP server;
I just now noticed this for the first time.  I wouldn't be surprised to
learn that it violates all kinds of RFCs, though.  It could be that
doing it that way makes it easier for them to block broadcasts from
noisy Windows clients, but that's just a guess.

                                        -- Bob Rogers
                                           http://rgrjr.dyndns.org/
 
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