<div style="white-space:pre-wrap">If you enable bpduguard it will err-disable the port(s) upon receipt of a BPDU. </div><br><div class="gmail_quote"><div dir="ltr">On Thu, Nov 10, 2016 at 8:44 AM Stephen Welsh <<a href="mailto:stephen.welsh@unifiedfx.com">stephen.welsh@unifiedfx.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">



<div style="word-wrap:break-word" class="gmail_msg">
<div class="gmail_msg">I thought that this would be prevented by default because of spanning tree/BPDU, but it’s common practice to disable spanning tree for access ports (i.e. using portfast) so that may allow the loop to occur, so maybe just disable port-fast?</div>
<div class="gmail_msg"><br class="gmail_msg">
</div>
<div class="gmail_msg">Kind Regards</div>
<br class="gmail_msg">
<div class="gmail_msg">
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" class="gmail_msg">
Stephen Welsh</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" class="gmail_msg">
CTO</div>
<br class="m_5877881828845622275Apple-interchange-newline gmail_msg" style="color:rgb(0,0,0);font-family:Helvetica;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:-webkit-auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
<span class="gmail_msg"><img height="16" width="100" id="m_587788182884562227560FDE1E2-04EF-4A69-BB58-AFFAE08957FA" src="cid:CBBF0493-235C-43D2-A874-9FB3D95AF598@b2.unifiedfx.com" class="gmail_msg"></span>
</div></div><div style="word-wrap:break-word" class="gmail_msg">
<br class="gmail_msg">
<div class="gmail_msg">
<blockquote type="cite" class="gmail_msg">
<div class="gmail_msg">On 10 Nov 2016, at 13:35, Ahmed Elnagar <<a href="mailto:ahmed_elnagar@hotmail.com" class="gmail_msg" target="_blank">ahmed_elnagar@hotmail.com</a>> wrote:</div>
<br class="m_5877881828845622275Apple-interchange-newline gmail_msg">
<div class="gmail_msg">
<div class="m_5877881828845622275WordSection1 gmail_msg" style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg">That is not nice at all<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span></span><span style="font-family:Wingdings;color:rgb(31,73,125)" class="gmail_msg">L</span><span style="color:rgb(31,73,125)" class="gmail_msg"><u class="gmail_msg"></u><u class="gmail_msg"></u></span></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg">Did you figure out a way to prevent it from switch side?<u class="gmail_msg"></u><u class="gmail_msg"></u></span></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></div>
<div class="gmail_msg">
<div style="border-style:solid none none;border-top-color:rgb(225,225,225);border-top-width:1pt;padding:3pt 0in 0in" class="gmail_msg">
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<b class="gmail_msg">From:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>Matthew Loraditch [<a href="mailto:MLoraditch@heliontechnologies.com" class="gmail_msg" target="_blank">mailto:MLoraditch@heliontechnologies.com</a>]<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span><br class="gmail_msg">
<b class="gmail_msg">Sent:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>Thursday, November 10, 2016 3:34 PM<br class="gmail_msg">
<b class="gmail_msg">To:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>Ahmed Elnagar <<a href="mailto:ahmed_elnagar@hotmail.com" class="gmail_msg" target="_blank">ahmed_elnagar@hotmail.com</a>>; '<a href="mailto:cisco-voip@puck.nether.net" class="gmail_msg" target="_blank">cisco-voip@puck.nether.net</a>' <<a href="mailto:cisco-voip@puck.nether.net" class="gmail_msg" target="_blank">cisco-voip@puck.nether.net</a>><br class="gmail_msg">
<b class="gmail_msg">Subject:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>RE: IP Phone Ports<u class="gmail_msg"></u><u class="gmail_msg"></u></div>
</div>
</div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<u class="gmail_msg"></u> <u class="gmail_msg"></u></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg">Yes it will create a loop. Not a fun time trying to track these things down. I’ve had some non-Cisco IP phones completely down a LAN.<u class="gmail_msg"></u><u class="gmail_msg"></u></span></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></div>
<div class="gmail_msg">
<p class="MsoNormal gmail_msg" style="margin:0in 0in 12pt;font-size:11pt;font-family:Calibri,sans-serif">
<span style="font-size:10pt;color:rgb(31,73,125)" class="gmail_msg">Matthew G. Loraditch – CCNP-Voice, CCNA-R&S, CCDA<br class="gmail_msg">
Network Engineer<br class="gmail_msg">
Direct Voice: 443.541.1518</span><span style="color:rgb(31,73,125)" class="gmail_msg"><u class="gmail_msg"></u><u class="gmail_msg"></u></span></p>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg"><a href="https://www.facebook.com/heliontech?ref=hl" style="color:rgb(149,79,114);text-decoration:underline" class="gmail_msg" target="_blank"><span style="font-size:8pt;color:blue" class="gmail_msg">Facebook</span></a></span><span style="font-size:8pt;color:rgb(31,73,125)" class="gmail_msg"><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>|<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span></span><span style="color:rgb(31,73,125)" class="gmail_msg"><a href="https://twitter.com/HelionTech" style="color:rgb(149,79,114);text-decoration:underline" class="gmail_msg" target="_blank"><span style="font-size:8pt;color:blue" class="gmail_msg">Twitter</span></a></span><span style="font-size:8pt;color:rgb(31,73,125)" class="gmail_msg"><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>|<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span></span><span style="color:rgb(31,73,125)" class="gmail_msg"><a href="https://www.linkedin.com/company/helion-technologies?trk=top_nav_home" style="color:rgb(149,79,114);text-decoration:underline" class="gmail_msg" target="_blank"><span style="font-size:8pt;color:blue" class="gmail_msg">LinkedIn</span></a></span><span style="font-size:8pt;color:rgb(31,73,125)" class="gmail_msg"><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>|<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span></span><span style="color:rgb(31,73,125)" class="gmail_msg"><a href="https://plus.google.com/+Heliontechnologies/posts" style="color:rgb(149,79,114);text-decoration:underline" class="gmail_msg" target="_blank"><span style="font-size:8pt;color:blue" class="gmail_msg">G+</span></a><u class="gmail_msg"></u><u class="gmail_msg"></u></span></div>
</div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<span style="color:rgb(31,73,125)" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></div>
<div class="gmail_msg">
<div style="border-style:solid none none;border-top-color:rgb(225,225,225);border-top-width:1pt;padding:3pt 0in 0in" class="gmail_msg">
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<b class="gmail_msg">From:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>cisco-voip [<a href="mailto:cisco-voip-bounces@puck.nether.net" style="color:rgb(149,79,114);text-decoration:underline" class="gmail_msg" target="_blank">mailto:cisco-voip-bounces@puck.nether.net</a>]<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span><b class="gmail_msg">On
 Behalf Of<span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span></b>Ahmed Elnagar<br class="gmail_msg">
<b class="gmail_msg">Sent:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>Thursday, November 10, 2016 8:28 AM<br class="gmail_msg">
<b class="gmail_msg">To:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>'<a href="mailto:cisco-voip@puck.nether.net" class="gmail_msg" target="_blank">cisco-voip@puck.nether.net</a>' <<a href="mailto:cisco-voip@puck.nether.net" style="color:rgb(149,79,114);text-decoration:underline" class="gmail_msg" target="_blank">cisco-voip@puck.nether.net</a>><br class="gmail_msg">
<b class="gmail_msg">Subject:</b><span class="m_5877881828845622275Apple-converted-space gmail_msg"> </span>[cisco-voip] IP Phone Ports<u class="gmail_msg"></u><u class="gmail_msg"></u></div>
</div>
</div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<u class="gmail_msg"></u> <u class="gmail_msg"></u></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
Dear all;<u class="gmail_msg"></u><u class="gmail_msg"></u></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<u class="gmail_msg"></u> <u class="gmail_msg"></u></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
I want to know what will happen if a user connect “by mistake” both the PC port and Switch port to the network switch? Will this create a loop? Anyone tried it before?<u class="gmail_msg"></u><u class="gmail_msg"></u></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<u class="gmail_msg"></u> <u class="gmail_msg"></u></div>
<div style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif" class="gmail_msg">
<u class="gmail_msg"></u> <u class="gmail_msg"></u></div>
</div>
<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important" class="gmail_msg">_______________________________________________</span><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" class="gmail_msg">
<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important" class="gmail_msg">cisco-voip
 mailing list</span><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" class="gmail_msg">
<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important" class="gmail_msg"><a href="mailto:cisco-voip@puck.nether.net" class="gmail_msg" target="_blank">cisco-voip@puck.nether.net</a></span><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" class="gmail_msg">
<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important" class="gmail_msg"><a href="https://puck.nether.net/mailman/listinfo/cisco-voip" class="gmail_msg" target="_blank">https://puck.nether.net/mailman/listinfo/cisco-voip</a></span></div>
</blockquote>
</div>
<br class="gmail_msg">
</div>

_______________________________________________<br class="gmail_msg">
cisco-voip mailing list<br class="gmail_msg">
<a href="mailto:cisco-voip@puck.nether.net" class="gmail_msg" target="_blank">cisco-voip@puck.nether.net</a><br class="gmail_msg">
<a href="https://puck.nether.net/mailman/listinfo/cisco-voip" rel="noreferrer" class="gmail_msg" target="_blank">https://puck.nether.net/mailman/listinfo/cisco-voip</a><br class="gmail_msg">
</blockquote></div>