Issues encountered with assigning .0 and .255 as usable addresses?

Paul Zugnoni paul.zugnoni at jivesoftware.com
Mon Oct 22 22:07:50 UTC 2012


Curious whether it's commonplace to find systems that automatically regard .0 and .255 IP addresses (ipv4) as src/dst in packets as traffic that should be considered invalid. When you have a pool of assignable addresses, you should expect to see x.x.x.0 and x.x.x.255 in passing traffic (ie. VIP or NAT pool, or subnets larger than /24). Yet I've run into a commercial IP mgmt product and getting reports of M$ ISA proxy that is specifically blocking traffic for an IP ending in .0 or .255.

Any experience or recommendations? Besides replace the ISA proxy…. Since it's not mine to replace. Also curious whether there's an RFC recommending against the use of .0 or .255 addresses for this reason.


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