Jima wrote: > Not quite. The magic number is 256 -- 0-255. Of that, three numbers >can't be used: 0 (the network address), 255 (the broadcast address), and >the gateway's address, which is usually either 1 or 254, depending on >administrator preference (although I've seen a random number in the middle >used). 0 and 255 are still totally usable, just not in a /24; you'd have >to go to /23 or bigger for them to be available (and I've heard some OSes >don't like using them; I don't know, though). A gateway address is only required, if a gateway to another subnet or network is desired. Even if a gateway is desired the gateway can clearly do more that route IP traffic, so I wouldn't say that its address is not useable for other purposes. However, Jima makes an important point that a gateway address has to be allocated from every subnet (or it will be an isolated subnet). Note that the gateway will consume an IP address from every subnet it is on, so sometimes there will be more than one IP consumed per subnet for gateway machines. Try a broadcast ping of your network address and broadcast address: # ping -b <network address> # ping -b <broadcast address> Notice the difference? Some devices will respond to a broadcast of the network address; others will not. It is a reserved address and use of it will cause unpredictable results! Don't use it, if you want predictability of operation. Sincerely, Ken Fuchs <kfuchs at winternet.com> _______________________________________________ TCLUG Mailing List - Minneapolis/St. Paul, Minnesota Help beta test TCLUG's potential new home: http://plone.mn-linux.org Got pictures for TCLUG? Beta test http://plone.mn-linux.org/gallery tclug-list at mn-linux.org https://mailman.real-time.com/mailman/listinfo/tclug-list