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?
Kind Regards Stephen Welsh CTO [cid:CBBF0493-235C-43D2-A874-9FB3D95AF598@b2.unifiedfx.com] On 10 Nov 2016, at 13:35, Ahmed Elnagar <ahmed_elna...@hotmail.com<mailto:ahmed_elna...@hotmail.com>> wrote: That is not nice at all ☹ Did you figure out a way to prevent it from switch side? From: Matthew Loraditch [mailto:mloradi...@heliontechnologies.com] Sent: Thursday, November 10, 2016 3:34 PM To: Ahmed Elnagar <ahmed_elna...@hotmail.com<mailto:ahmed_elna...@hotmail.com>>; 'cisco-voip@puck.nether.net<mailto:cisco-voip@puck.nether.net>' <cisco-voip@puck.nether.net<mailto:cisco-voip@puck.nether.net>> Subject: RE: IP Phone Ports 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. Matthew G. Loraditch – CCNP-Voice, CCNA-R&S, CCDA Network Engineer Direct Voice: 443.541.1518 Facebook<https://www.facebook.com/heliontech?ref=hl> | Twitter<https://twitter.com/HelionTech> | LinkedIn<https://www.linkedin.com/company/helion-technologies?trk=top_nav_home> | G+<https://plus.google.com/+Heliontechnologies/posts> From: cisco-voip [mailto:cisco-voip-boun...@puck.nether.net] On Behalf Of Ahmed Elnagar Sent: Thursday, November 10, 2016 8:28 AM To: 'cisco-voip@puck.nether.net<mailto:cisco-voip@puck.nether.net>' <cisco-voip@puck.nether.net<mailto:cisco-voip@puck.nether.net>> Subject: [cisco-voip] IP Phone Ports Dear all; 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? _______________________________________________ cisco-voip mailing list cisco-voip@puck.nether.net<mailto:cisco-voip@puck.nether.net> https://puck.nether.net/mailman/listinfo/cisco-voip
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