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SUMMARY: Question about subnetting /24's
I got several requests emailed to me personally from other network operators who also wanted this information, so I'm posting a summary back to the list. If you feel this information is beneath you, by all means stop reading right now! :) Basically, the reason why I had to go out of my way to enable the subnet where the network portion of the last octet was all-zeroes or all-ones is a relic from Ancient Times (read: about 18 months ago), when classful networking was everywhere, and RIPv1 walked its hallowed halls. RIPv1 does not send subnet information in its route announcements, so the subnet that contained the Class C network and broadcast address were off-limits. While many routers come this way by default (a situation which one respondant described as "abominable"), everyone seemed to be in agreement that any router that did not totally suck would let me turn this off. A few others added to this that they felt my Bay Networks router *did* totally suck. As proof that this isn't the case (at least not this time), the problem ended up being completely unrelated to the subnetting. But I was still curious. On a Cisco, the command is "ip subnet-zero" and "ip classless". On a Bay, the "Enable zero subnet" button in Site Manager does the trick. As backup ammo against future tech support incidents, several people pointed out RFC 1878 and 1519, which lays all this out. With regards to reverse DNS, several people pointed me to the advice in RFC 2137. It's just a few pages, and sums up the situation better than I could. Thanks to the numerous people who responded by private email, -------Scott.