From: Pavel Bykov (slidersv@gmail.com)
Date: Fri Feb 20 2009 - 10:05:04 ARST
You did good.
What you should not forget, is that RFC1918 could be subnetted, which is
permitted under the rules, meaning you maybe should deny the ranges up to
the limit of 32 bits. But you should check that with proctor maybe.
Otherwise, 127.0.0.0 and 169.254.0.0 are not correct answer.
These pertain to "Special uses IPs":
http://tools.ietf.org/html/rfc3330
127.0.0.0 is guided by a separate RFC = 1700
and 169.254.0.0 is a historic network. It was acquired by Microsoft to have
all it's PCs talk to each other if the DHCP is not found. Therefore if two
Microsoft-based PCs were connected to a network and were not able to find
any IP address (manual/DHCP) they would set a "random" address from
169.254.0.0 range. Therefore they would be able to talk to each other. Now
it is transformed into IPv4 "Link Local" range.
That's the legend anyway.
On Tue, Feb 17, 2009 at 1:31 PM, John Ciccone <ccie.ciccone@gmail.com>wrote:
> I recently took a vendors mock lab where the task asked block all RFC1918
> adddress. So, I created an access-list and applied it to deny the
> following:
>
> 10.0.0.0/8
> 172.16.0.0/12
> 192.168.0.0/16
>
> I've read RFC1918 from top to bottom, and the above addresses are the only
> ones mentioned. However, upon checking my answers with the solutions, they
> also included the following:
>
> 127.0.0.0/8
> 169.254.0.0/16
>
> Now, while the above addresses are not valid internet addresses, they are
> NOT RFC1918 addresses. If the question stated that I should block non
> valid
> internet addresses, then I could see denying the two ip blocks above as
> well. But even in that case, there are at least a half dozen more ipv4
> blocks that are either not valid or not yet allocated for the internet.
>
> My main question is this: If I get the same type of task on the actual lab,
> what do I do? Will the questions be specific enough to leave no doubt
> as to what they are looking for (not only for this type of questions, but
> any others as well)? If there are any doubt's about what they are looking
> for, how helpful will the proctor be in clarifying?
>
> I am scheduled to take the lab in 3 weeks, so any help would be greatly
> appreciated.
>
> John
>
>
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-- Pavel Bykov ---------------- Don't forget to help stopping the braindumps, use of which reduces value of your certifications. Sign the petition at http://www.stopbraindumps.com/Blogs and organic groups at http://www.ccie.net
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