nanog mailing list archives

Re: The use of .0/.255 addresses.


From: "Stephen J. Wilcox" <steve () telecomplete co uk>
Date: Sun, 27 Jun 2004 17:12:17 +0100 (BST)



On Sun, 27 Jun 2004, Peter Corlett wrote:


Stephen J. Wilcox <steve () telecomplete co uk> wrote:
[...]
I currently have a few .255/32s with Cisco and Foundry products and
have various windows/linux/OSX machines that access them without
problems..

Well, I'd expect Linux and OSX to do the right thing. It just seems to
be Windows that makes a complete sow's ear of it.

As to the IP addresses ending in 255 that are working from Windows
boxes, would I be right in guessing that the first octet of the IP
addresses in question is between 1 and 191?

Hi Peter,

actually no.. I just did a test right now, I'm at a friends and using an XP 
machine connected via a cable modem.. my results arent entirely in agreement 
with my initial post

I tested to both a "Class A" .255 we have and also to a "Class C" .255 we have

Class A: works on everything..trace, ping, ssh

Class C: spooky, traces up to the interface before the device. wont ping. 
connections fail with Network error: Cannot assign requested address. But, this 
same test works when tried from linux - possibly different behaviour between 
icmp and udp on cisco??

From the hop-before-last (cisco 7206 12.2(14)S3) if i ping it seems to be
broadcasting out of the interface towards the .255 rather than unicasting, i
confirm this with a packet capture:

16:03:47.614187 Class-C.x.x.x > 255.255.255.255: icmp: echo request

the cisco reports correct routing of the Class-C /32 

Steve


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