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<div class="moz-cite-prefix">On 12/13/2013 02:31 PM, Edward Holcroft
wrote:<br>
</div>
<blockquote
cite="mid:CAN8XfE9urB2do2amegidtwoOjmSi9d0d39ypbUxc5FbPjqG2vA@mail.gmail.com"
type="cite">
<div class="gmail_default" style="font-size:small">What is
5.x.x.x? I've never heard of them before and am I allowed to use
them? More importantly, where are they coming from? I never set
anything to offer IP's in that range, unless it's some kind of
default.</div>
</blockquote>
<br>
The whois utility can tell you a good bit:<br>
<ul>
<li>5.0.0.0/8 is <b>allocated</b> for assignment by RIPE, meaning
that these addresses belong in Europe.<br>
</li>
<li>Various chunks of it are assigned to ISPs and backbone links
(e.g. 5.0.0.0/17).</li>
</ul>
<p>This means that you should absolutely not be using these IP
addresses, as they <i>will</i> conflict with the public Internet.<br>
</p>
<p>Verify that the configuration of the server handing out the
addresses is correct; even Microsoft products should not
intentionally be using IP address space that is not allocated to
it, unless some administrator in the admin chain told it to
figuring that it wouldn't hurt anything.<br>
</p>
<p>Remember the private IPv4 networks:<br>
</p>
<ol>
<li>10.0.0.0/8 if you need something very large.</li>
<li>172.16.0.0/12 if you need something moderately large and
nonconflicting.</li>
<li>192.168.0.0/16 if you need something recognizable. I don't
use this range anymore, myself.</li>
</ol>
<p>I also use the TEST-NET-1 through TEST-NET-3 allocations for
LAN-only testing of development apps and systems, but I never
deploy anything with those addresses.<br>
</p>
<p>For dial-in and VPN access, you should be using either addresses
assigned to you by your upstream (e.g., your ISP or ARIN), RFC1918
space (one of the three ranges listed above), or assigned,
delegated or organization-local IPv6 addressing.<br>
</p>
<p>Ideally, the VPN should be its own routed subnet. This isn't
always possible though, so many VPN servers will actually do
proxy-ARP to make the VPN-connected peers appear to be on the
local subnetwork.<br>
</p>
<p> — Mike<br>
</p>
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<td> Michael B. Trausch<br>
<br>
President, <strong>Naunet Corporation</strong><br>
☎ (678) 287-0693 x130 or (855) NAUNET-1 x130<br>
FAX: (678) 783-7843<br>
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