OK, I've tried it on a router with 12.1.1 and same results. None of these
wacky subnets allowed.
Windows 98 still permits this kind of stuff. How about Win2K? Any of you
folks want to report if Microsoft is compliant yet?
BTW, a quick glance through the RFC reveals that Unix boxes ( mentioned by
name, but applies to all OS's ) with a single NIC should not have routing
turned on as a matter of compliance.
RFC 1812 states specifically that
The bit positions containing this extended network number have historically
been indicated by a 32-bit mask called the subnet mask. The bits SHOULD be
contiguous and fall between the and the fields. More up to date protocols do
not refer to a subnet mask, but to a prefix length; the "prefix" portion of
an address is that which would be selected by a subnet mask whose most
significant bits are all ones and the rest are zeroes. The length of the
prefix equals the number of ones in the subnet mask. This document assumes
that all subnet masks are expressible as prefix lengths.
And
Architecturally correct subnet masks are capable of being represented using
the prefix length description. They comprise that subset of all possible
bits patterns that have a contiguous string of ones at the more significant
end, a contiguous string of zeros at the less significant end, and no
intervening bits.
Lastly
Routers SHOULD always treat a route as a network prefix, and SHOULD reject
configuration and routing information inconsistent with that model.
The word SHOULD in RFC land is pretty strong. Therefore a compliant router
will not accept a wacky mask. I presume this includes 3Com, Nortel, and
Lucent as well, if anyone wants to verify with those vendors.
To get back to the original question then, the answer is FALSE
I gotta remember to unlearn all the bad things I learned as a Windows
network administrator :->
Chuck
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Dale
Cantrell
Sent: Monday, September 04, 2000 5:27 AM
To: [EMAIL PROTECTED]
Subject: RE: Subnet Question
----Original Message Follows----
From: Albert Ip <[EMAIL PROTECTED]>
Reply-To: Albert Ip <[EMAIL PROTECTED]>
To: "'Chuck Larrieu'" <[EMAIL PROTECTED]>, Aaron Moreau-Cook
<[EMAIL PROTECTED]>, [EMAIL PROTECTED]
Subject: RE: Subnet Question
Date: Sun, 3 Sep 2000 19:14:11 -0700
Chuck,
Just tried it on a 3662 with IOS 12.1T and it didn't work.
Rotuer(config-if)#ip address 10.1.1.1 0.255.255.0
Bad mask 0xFFFF00 for address 10.1.1.1
Too bad, it would had made a interesting trouble-shooting lab.
Albert
-------------------------------------------------------------------------
Hi Albert,
I'm familiar with Classfull, Classless Ip addressing, but how would a person
go about symplifing one of these unusual masks to an address i.e.-
10.1.1.1/16 ? The ones are right, BUT, where would someone know WHICH
octets, you were referring to????? Would you just have to type the full
address and mask.
If they don't work anyway, this is a null point.
Thanks
Dale CCNA?
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