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

Joe Greco jgreco at
Mon Oct 22 23:07:10 UTC 2012

> d 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 N=
> AT pool, or subnets larger than /24). Yet I've run into a commercial IP mgm=
> t product and getting reports of M$ ISA proxy that is specifically blocking=
>  traffic for an IP ending in .0 or .255.

To make a long story short:

If it's a product you're considering buying, problems with .0 and .255
reflect on the competence of the product's designers.  You can safely
assume that there are many other Severely Broken Things too and move on
to saner products.

For general Internet use, there is a lot of gear out there that's ten or
more years old.  You should avoid using .0 and .255 addresses if you can
avoid it, though it's a shame to waste valid IP space to accommodate the
brokenness of someone else's stuff.

Some of us park stuff on .0 and .255 addresses in order to motivate 
others to change.

... JG
Joe Greco - Network Services - Milwaukee, WI -
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

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