Networking Knowledge Base

ResolutionTo protect access to privileged EXEC and configuration modes, issue the enable password and enable secret commands. The enable password command password can be recovered. However, the enable secret command password is encrypted and can only...

Core issueThe Port Aggregation Protocol (PAgP) attempts to remove a port not in the spanning tree data structure, causing this error message to be generated.ResolutionThe %SPANTREE-3-PORTDEL_FAILNOTFOUND:9/5 in vlan 10 not found (PAgP_Group_Rx) messa...

Core IssueThe most common reason for this problem is having a filter policy applied to the redistribution statement, which denies the networks in question.  Another possibility is that the router has the auto-summary command enabled under the Border ...

Core IssueRoute Redistribution is used to propagate routes learned using one protocol, into another routing protocol. When BGP is redistributed into an IGP, only eBGP learned routes get redistributed. The iBGP learned routes known on the router are n...

Core IssueContext-based Access Control (CBAC) is a Cisco IOS  Firewall feature that allows filtering of traffic using Access Control Lists (ACLs). CBAC allows closer inspection of protocols before permitting traffic through, which provides higher per...

Core issueThis problem ocuurs most commonly when the device ( to which the user is trying to connect using telnet and ssh ) dosen't have the proper user credentials or there is a connectivity problem to the device.ResolutionTo resolve this issue, per...

ResolutionThese are the guidelines and restrictions to configure Switched Port Analyzer (SPAN):Use a network analyzer to monitor interfaces.      Do not mix source VLANs and filter VLANs within a SPAN session. Source VLANs and filter VLANs cannot co-...

Core IssueThe Cisco 1600 series routers are produced in two versions: the 1600 and the 1600-R. The Cisco 1600 series router images run from Flash, while the 1600-R series router images run from RAM. Therefore, these are the two different types of Cis...

Core issueStatic routes are seen in show running-config but not in show ip route command output.You can display all active dynamic static routes with both the show ip route and show ip route static commands after these active routes are added in the ...

ResolutionThere is no configuration option to clear port channel configuration in CatOS. As a workaround, complete these steps in order to clear the unused port channel configs:Use the copy config tftp command in order to backup the configurations to...

Core issueThe Cisco Catalyst 3560 Small Form-Factor Pluggable (SFP) Interconnect Cable (Part No. CAB-SFP-50CM=) provides for a low-cost, point-to-point, Gigabit Ethernet connection between Catalyst 3560 Series Switches. The 50-centimeter (cm) cable i...

Core issueThese messages can appear in the logs:%C6KENV-SP-STDBY-4-FANPSINCOMPAT: Fan tray and power supply 1 are incompatible%C6KENV-SP-STDBY-4-FANPSINCOMPAT: Fan tray and power supply 2 are incompatible%C6KENV-SP-2-SHUTDOWN_SCHEDULED: shutdown for ...

Core IssueThe most common reason for this issue is a problem with the outbound Border Gateway Protocol (BGP) filtering policy. The show ip bgp neighbor command shows which filters are being applied per neighbor.ResolutionEnsure that the outbound BGP ...

Core issueA Supervisor Engine 720 can crash because the Ethernet Out of Band Channel (EOBC) channel is jammed when you insert a second Supervisor Engine 720 in the chassis. This symptom is observed on a Cisco Catalyst 6500 series and a Cisco 7600 ser...

Core issueThis means an Remote Monitoring (RMON) register has overflowed (wrapped around).The situation in which the area where the RMON statistical information is stored, has overflowed (wrapped around) is shown with MAC interface 1 of Sibyte ethern...