Loopback Error
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Pm 4 Err_disable Bpduguard Error Detected
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Pm-4-err_disable Channel-misconfig (stp) Error Detected
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to find this is in the output of show interfaces status. A switch port can end be error
Pm-4-err_disable Psecure-violation Error Detected
disabled if the software (IOS or CatOS) detects an error %ethcntr-3-half_dux_collision_exceed_threshold situation on the port. The port is effectively shut down until re-enabled manually or automatically if a cscea46385 recovery timer is specified for the error condition. One such error condition results from the existence of a loopback on the port. The switch sends keepalive packets https://supportforums.cisco.com/discussion/10905251/pm-4-errdisable-loopback-error-detected-gi02 out all interfaces. If a keepalive packet is received on the same interface it was sent from, then a loop exists that has not been blocked by Spanning-Tree Protocol. If this occurs, these messages are generated (these specific messages are from a Cisco Catalyst 2940). %ETHCNTR-3-LOOP_BACK_DETECTED: Keepalive packet loop-back detected on FastEthernet0/3.
%PM-4-ERR_DISABLE: loopback https://slaptijack.com/networking/err-disabled-loopback-edition/ error detected on Fa0/3, putting Fa0/3 in err-disable state
To resolve the problem, you must investigate the network beyond the port that is complaining and discover what sort of logical loop might exist that was undetectable by STP. Often, less capable devices (inexpensive unmanaged switches or hubs) are the culprit. Related Reading: Cisco Field Manual: Catalyst Switch Configuration by David Hucaby, Stephen McQuerry Building Cisco Multilayer Switched Networks by Richard Froom, Balaji Sivasubramanian, Erum Frahim Related Posts UDLD In Radio-Based Metro Ethernet Rings Cisco Catalyst 3560 POST Output Allowing DHCP Option 82 in Cisco DHCP Relay Agents Brand New ME3400G Can't Ping! 3 Reasons You Should Be Using Rapid Spanning Tree (802.1w) Get Slaptijack updates delivered to your Inbox or RSS Reader for free! CATEGORIES Graphics Design Information Systems IT Management Networking Programming Software System Administration Uncategorized Voice / Voice over IP ARCHIVES 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 © 2016 Slaptijack All Rights Reserved · Wordpress
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IP isWhoisCalculatorTool PointsNewsNews tip?ForumsAll ForumsHot TopicsGalleryInfoHardwareAll FAQsSite FAQDSL FAQCable TechAboutcontactabout uscommunityISP FAQAdd ISPISP Ind. ForumsJoin Search similar:Cisco SAP-1602i connected to 2960 trunk port[HELP] Transit VRF Question[Config] Performance due to VLAN, incomplete STP, or loop backs?[Config] Cisco Switches Trying to Carry a VLAN's trafficCisco 887VA-M-K9 can't ping local LAN or the other way around Forums → Equipment Support → Hardware By Brand → Cisco → [HELP] Figuring out the reason behind err-disabled loopback. uniqs1579 Share « VLAN question • A little update on daily fun » techsup1983join:2013-03-23 techsup1983 Member 2015-Jun-20 4:47 am [HELP] Figuring out the reason behind err-disabled loopback.Hello all.We have a core switch (WS-C3650-48PD) and there are ports which keep showingPort Name Status Reason Err-disabled VlanGi2/0/19 err-disabled loopbackis it a good idea to do the no keepalives command on the ports or would there be a way to get more information.What would be the best way to troubleshoot this?Please ask me for anything i've not mentioned. Thanks. · actions · 2015-Jun-20 4:47 am · tired_runnerPremium Memberjoin:2000-08-25New York tired_runner Premium Member 2015-Jun-20 9:49 am Please draw up a quick and dirty MS Paint diagram of your topology, particularly where your 3650 connects to other switches. · actions · 2015-Jun-20 9:49 am · markysharkeyPremium Memberjoin:2012-12-20united kingd markysharkey to techsup1983 Premium Member 2015-Jun-21 11:52 am to techsup1983err-disable loopback could be because storm control is enabled on the port and it keeps seeing BPDU's and/or traffic from a loop.As well as the diagram Network Guy has asked for lets have see the output for the following:show run int gi 2/0/19 sho int gig 2/0/19 sho int trunk shp spanning-tree vlan x (where x is the native VLAN) The only time I see a port with the spanning-tree port-state listed as loopback is where every switch in a topology has had spanning tree disabled except for one. I used to demo this in a lab environment when I taught CCNA and was showing switching loops and how to deal with them. · actions · 2015-Jun-21 11:52 am · HELLFIREMVMjoin:2009-11-25 HELLFIRE to techsup1983 MVM 2015-Jun-21 1:51 pm to techsup1983My