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<p class="MsoNormal"><span style="color:#1F497D">></span>Why do you think the network portion needs to be contiguous?<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Just because some equipment at one time let you configure a non-contiguous mask does not make it correct configuration. Please come up with any valid use case
for a non-contiguous network (note NETWORK, not any other purpose) mask.<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span>Well, it does now. But that was not always the case.<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">It has ALWAYS been the only correct way to configure equipment and is a requirement under CIDR. Here were your commonly used netmasks before CIDR/VLSM :<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">255.0.0.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">255.255.0.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">255.255.255.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Which one is not contiguous?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span><a href="https://www.quora.com/Why-is-the-subnet-mask-255-255-255-64-invalid/answer/Patrick-W-Gilmore">https://www.quora.com/Why-is-the-subnet-mask-255-255-255-64-invalid/answer/Patrick-W-Gilmore</a><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">In this example, the writer used it as a parlor trick to actually break a network. That’s why you don’t do it and it was never a good configuration. It just
exploited a UI that did not validate the netmask.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span><a href="https://www.quora.com/Why-is-the-subnet-mask-255-255-255-64-invalid">https://www.quora.com/Why-is-the-subnet-mask-255-255-255-64-invalid</a><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">In the second cited link, they are talking about using a non-contiguous mask in an access control function. That is perfectly valid to do, it just is not a NETmask
anymore. By definition a netmask identifies the network portion of an address. In the cited example they are defining a group of subnets to an ACL.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Steven Naslund<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Chicago IL<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span><span style="color:black">-- <br>
</span><span style="color:#1F497D">></span><span style="color:black">TTFN,<br>
</span><span style="color:#1F497D">></span><span style="color:black">patrick<o:p></o:p></span></p>
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