CCNP TSHOOT Quick Reference Sheet Exam 300-135
Chapter 1. Network Principles Troubleshooting Steps Problem Identification Collection of Information Examination and Action Plan Verification Basic Troubleshooting Tools GUI Tools Cisco Configuration Professional (CCP) SNMP Agent & other Applications. CLI Tools CLI Tools Show Debugging Ping Extended Ping Traceroute Extended Traceroute Show Command The command "show" is very popular, helpful for the network administrator. It displays the information, configuration, routes and much more that is running on a network device. Switch# show running-config Router# show running-config Switch# show version Router# show version etc. Debugging Redirect Debugging Console VTY Line Internal Buffer Syslog Server Conditional Debugging Protocol Specific Router# Debug [Protocol] Router# No Debug [Protocol] Conditional Router# Debug Condition Interface [Interface] Router# No Debug Condition Interface [Interface] Multiple Condition Extended Ping Size 100 Bytes (default) Number of Bytes per Datagram Repeat 5 packets (default) Number of Packets to be send Timeout 2 Sec (default) Time to wait for Echo reply Source Outgoing Interface (default) Source Address, if not configured, Take Outgoing interface address Don t Fragment bit disable (default) By default Don t fragment bit is disabled. If enabled, drop the packet if fragmentation needed Extended Traceroute Protocol [IP] (default) Supported Protocol Option, like AppleTalk, CLNS, IP, Novell etc. Target IP Destination IP address Source IP Source IP address, if not mentioned, take Outgoing interface address by default Numeric Display By default, suppressed the output is shown hence disabled. Timeout Default Timeout is 3 Secs Probe Count Number of Probe send on each TTL. Default value is 3. Minimum TTL Minimum Time to Live value, (1 by default). Maximum TTL Maximum Time to Live value, (30 by default). Port No Destination Port used by UDP Probe, default is port no 33434 Other Options Other IP header Options like Loose, Strick, Timestamp, verbose etc.
Chapter 2. Layer 2 Technologies Switch Administration Port Error Check Cabling and Connector Check for Straight through and Crossover Cable Enable Auto MDIX Feature Duplex Error Check for Collusion and No of Packets sent and Receive Enable Auto Negotiation Check for Duplex setting and Speed Options are Dull Duplex Half Duplex Auto Negotiation SDM Template SDM is Switching Database Manager. It is used to manage the switching information of Layer 2 up to Layer 3. For this, Ternary Content Addressable Memory or TCAM is used. Basic purpose of TCAM is forwarding Lookups. As far as SDM Templates are concerned, there are four templates Access Template VLAN Template Default Template Routing Template Troubleshooting MAC Address Troubleshoot Specific MAC Address in Table Switch# Show mac-address-table [address] Troubleshoot Aging Time of MAC Address Switch# Show mac-address-table aging-time Troubleshoot Dynamic MAC Addresses Switch# Show mac-address-table dynamic Troubleshoot Count of MAC Addresses Switch# Show mac-address-table count Troubleshoot MAC Address bind to an interface Switch# Show mac-address-table interfaces Error Disable Recovery When the IOS of Switch detect the error encountered on any port, it brings the port into error disabled mode. In Error disabled mode, the port is shut down and no traffic is passing in or out from the port. The Port LED turn Orange when the port is in error disabled mode. Commands: Switch(config)#errdisable detect cause security-violation shutdown vlan Switch(config)#errdisable recovery cause security-violation Troubleshooting Layer 2 Protocol Cisco Discovery Protocol (CDP) Cisco Discovery Protocol is a layer 2 protocol for all cisco devices and for all network management applications to discover the cisco devices at the neighbour. Enabled Globally by default Configuring CDP CDP are enabled by default on Cisco devices. However, following command is used to enable it: Switch(config)# cdp run To disable CDP, following command is implemented: Switch(config)# No cdp run Troubleshooting CDP Switch# show cdp Switch# show cdp traffic Switch# show cdp neighbours [interface-id] [detail] Switch# show cdp interface [interface-id] Link Layer Discovery Protocol (LLDP) As the Cisco devices are allowed to share information at layer 2 using CDP protocol, IEEE developed a protocol 802.1AB for the support of Non Cisco devices which also run over layer 2. Switch(config)#lldp run Switch(config)#int eth 0/0 Switch(config-if)#lldp transmit Switch(config-if)#lldp receive Unidirectional Link Detection Protocol (UDLD) UDLD- Enable Mode (default) To enable Switch(config)# udld enable UDLD- Aggressive Mode To enable Switch(config)# udld aggressive Troubleshooting VLAN VLAN ID VLAN 1 Default VLAN (Can use, cannot modify) VLAN 2-1005 (Can Use and Modify) VLAN 1006-3967 (Extended) VLAN 3968-4094 (Internally Allocated) Troubleshooting VLAN Port Switch#show Vlan VLAN Ports Access Port Can carry only one Vlan Switch(config-if)#switchport mode access Trunk Port Carry Multiple Vlan Switch(config-if)#switchport mode trunk Dynamic Can Negotiate to turn the port Access or Trunk Switch(config-if)#switchport mode dynamic Troubleshooting VLAN Port Switch#show interface [interface-type] [interface number] switchport Troubleshooting EtherChannel Layer 2 Ether Channel Port Aggregation Control Protocol Link Aggregation Control Protocol On (Manual) Switch#show etherchannel [number] detail Layer 3 Ether Channel Router#show int port-channel [number] Troubleshooting Spanning Tree Protocol Spanning Tree Protocol (STP) Switch#show spanning-tree Switch#show spanning-tree summary Switch#show spanning-tree detail Switch#show spanning-tree interface [type] [Number] Per Vlan Spanning Tree + (PVST+) Switch#show spanning-tree Switch#show spanning-tree summary Switch#show spanning-tree detail Switch#show spanning-tree interface [type] [Number] Multiple Spanning Tree (MST) Switch#show spanning-tree mst Switch#show spanning-tree mst configuraiton Switch#show spanning-tree mst interface [type] [Number]
Chapter 3. Layer 3 Technologies IPv4 DHCP Relay and Server Troubleshooting IP address Ipconfig (Command Prompt of DHCP Client) Troubleshooting IPv4 settings Control Panel/ Network Adapter Setting (PC) Router# show ip dhcp binding (DHCP Server Router) Router# show ip dhcp conflict (DHCP Server Router) Troubleshooting the Helper Address configured on the Router Nearest to the Client Router# show ip int eth 0/0 (Relay Agent Router) Router# show run Section interface (Relay Agent Router) Troubleshooting the DHCP Pool is defined. Router# show run Section IP dhcp (DHCP Server Router) Router# show ip dhcp pool (DHCP Server Router) Troubleshoot the Routing from Server to the Relay Agent IPv6 DHCP Relay and Server Troubleshooting the IP address is obtained by the Client. Ipconfig (Command Prompt of DHCP Client) Troubleshooting IPv4 settings Control Panel/ Network Adapter Setting (PC) Router# show ipv6 dhcp interface (Relay Router) Router# show ipv6 dhcp interface (Server Router) Troubleshooting the DHCP Pool is defined. Router# show ipv6 dhcp pool (Server Router) Enable IPv6 Unicast Routing Router(config)#ipv6 unicast-routing Troubleshoot IPv6 Routing Router# show ipv6 route Passive Interface Troubleshooting Passive interface Configuration Router# show ip [ospf / Eigrp] interface Router# show run Section interface Router# show run Section ospf Troubleshooting Routing Updates Blocked by Passive Interface Router# Show ip route Router# show ip [ospf/eigrp] neighbors Troubleshooting VRF-Lite Troubleshoot the VRF Configuration Router# show ip vrf brief Router# show ip vrf detail Troubleshoot the VRF interfaces Router# show ip vrf brief Router# show run Section interfaces Router# Show ip vrf interface [vrf-name] Troubleshooting VRF Routing table vrf [vrf-name] Troubleshooting Filtering and Redistribution Troubleshoot for the configuration of Filtering and Redistribution configuration Router# show run Troubleshoot for the configuration of Filtering and Redistribution. Troubleshooting PBR Configuration Router# show ip interface Ethernet [Number] Router# show access-list Router# show route-map Troubleshooting PBR Router# Traceroute [destination ip] Router# show route-map Troubleshooting EIGRP Troubleshooting Neighbor, Topology, Successor, Routing table etc. Router# show ip eigrp neighbors Router# show ip eigrp topology Router# show ip Route Router# show ip eigrp events Troubleshooting Timer and Traffic Router# show ip eigrp timer Router# show ip eigrp traffic Troubleshooting EIGRP metric and IP Parameters Router# show ip protocols Router# show eigrp protocols Troubleshooting EIGRP Authentication Router# show run Section interface Troubleshooting EIGRP Load Balancing [destination IP] Router# show ip eigrp topology Troubleshooting EIGRP Stuck In Active (SIA) Router# show ip eigrp topology Router# show ip eigrp neighbors detail Troubleshooting EIGRP Stub Router# show run Section router eigrp Router# show ip protocols Router# show eigrp protocols Troubleshooting EIGRP IPv6 Must Enable IPv6 Routing Must Enable EIGRP on an interface Assign Eigrp Router ID Router# show ipv6 Route Router# show ipv6 eigrp events Router# show ipv6 eigrp interfaces Router# show ipv6 eigrp neighbours Router# show ipv6 eigrp sia-statistics Router# show ipv6 eigrp timer Router# show ipv6 eigrp topology Router# show ipv6 eigrp traffic Troubleshooting OSPF Troubleshooting OSPF Neighbor and Routes: Router# show ip ospf neighbor Troubleshooting OSPF Interfaces Router# show ip ospf interface Ethernet [number] Router# show ip ospf interface brief Troubleshooting OSPF LSA Types Router# Show ip ospf database Troubleshooting OSPF Parameters Router# show ip ospf events Router# show ip ospf topology-info Router# show ip ospf traffic Remember Turn UP the interface Assign IP Address Enable OSPF Introduce Route to OSPF
Troubleshooting OSPFv3 Remember Enable IPv6 unicast Routing Turn UP the interface Assign IPv6 Address Enable OSPF on an Interface Assign Router ID Troubleshooting OSPFv3 Router# show ipv6 route Router# Show ipv6 Ospf neighbor Default Routing Troubleshooting Commnads: Try to make ping. Troubleshooting BGP Troubleshooting Border Gateway Protocol (BGP) must include some the these parameters Configure Autonomous System Correctly Configure Correct IP address of Neighbor with Correct Autonomous System Number for ebgp Define Internal Network for ibgp Turn UP the interfaces Troubleshooting BGP Neighbors, Routes Router# show bgp neighbors Router#show ip route Router# show ip bgp summary Router# show bgp ipv4 unicast summary Router# show ip bgp topology Rotuer# shwo run Section Router bgp Static Routing Comamand: Router(config)# ip route [Network IP] [Prefix] [Next Hop IP address Outgoing interface ] Troubleshooting Commnads: Try to make ping to the network Introduce statically By default Static Route has the Administrative Distance of 1. If AD value is modified, Make sure to make it preffered or backup route.
Chapter 4. VPN Technologies Troubleshooting GRE Tunnel Turn UP the Tunnel interface. Router# show ip int brief Assign IP address to turn Portocol Up Router# show ip int brief Make Sure the Source and Destination IP address Router# show int tunnel [Number] Verify the Tunnel mode [IP/GRE] Router# show int tunnel [Number] Check the Access-list Router# show access-list Troubleshoot the MTU Size Router# show ip interface ethernet [Number] Router# show int tunnel [Number] Troubleshoot the Routing Protocol
Chapter 5. Infrastructure Security AAA Using Local Database Configuring AAA Local Database Enable AAA Model Router(config)# aaa new-model Enable Authentication by Local Database (Radius and TACAC+ can also Configured) Router(config)# aaa authentication login default local Enable Authentication on Lines (Console, VTY and Aux) Router(config-line)#login authentication default Configure a Username and Password Configure Enable password Use Service password Encryption Access from Console Line to Verify the Username and Password Authentication Access from VTY Line to Verify the Username and Password Authentication Troubleshooting Device Access Control Configure a Username and Password Router# username [NAME] password [keyword] Configure Enable password Router# enable Secret [password] Use Service password Encryption Router# service password-encryption Enable Authentication on line Router(config-line)#login local Allow SSH for VTY Lines for Secure Access Router(config)# line vty 0 4 Router(config-line)# transport input ssh Allow SSH for Secure communication instead of transport input all. Use Service password encryption for Encryption Use RSA algorithm for SSH Use Management Plane Protection Shutdown the unnecessary ports. Troubleshooting Standard Access Control List Standard Access Control List Range 1-99 & 1300-1999 Apply to an interface Apply in correct Direction Apply the statement in the manner that it will not affect the network. Don t Permit any or Deny any in the first statement of ACL. Router# show access-list section interface Troubleshoot Extended Access Control List Standard Access Control List Range 100-199 & 2000-2699 Apply to an interface Apply in correct Direction Apply the statement in the manner that it will not affect the network. Don t Permit any or Deny any in the first statement of ACL. Router# show access-list section interface Router# show ip interface [Type] [Number] Troubleshooting IPv6 Traffic Filter Enable IPv6 Unicast Routing Apply Traffic Filter to an interface Apply in correct Direction Apply the statement in the manner that it will not affect the network. Don t Permit any or Deny any in the first statement of ACL. Make sure while configuring the sequence number that first statement will not affect the next statement. Router# show ipv6 access-list section interface Router# show ipv6 interface [Type] [Number] Troubleshooting urpf Router(config)#int eth 0/0 Router(config-if)#ip verify unicast source reachable-via rx Must Enable CEF to support urpf. Routing Table must have the entry. Router# show cef interface [Type] [Number] Router#show ip int ethernet 0/0 section IP
Chapter 6. Infrastructure Services Troubleshooting SNMP Router(config)#snmp-server group [NAME] v3 auth read ABCview NAME is the group name, must be the same at Agent v3 is used for SNMP version 3 v2 is used for SNMP version 2 Use the same version at both side. Router(config)#snmp-server user [NAME] [Group] v3 auth md5 [password] Create a username and Password with Authentication Algorithm (Supported by v3 only) Username Password must be the same. Group name is the group in which user lies. Check the connectivity of SNMP Agent by ping Check the Routing table to have an entry for SNMP agent Check if SNMP Agent running SNMP Agent Software Troubleshooting Logging Commands Enable logging on default destinations R1(config)#logging on Trap debug R1(config)#logging trap debugging Enable time stamp on debug R1(config)#service timestamps debug datetime msec Enable time stamp on log R1(config)#service timestamps log datetime msec Enable Debug IP routing Router# debug ip routing Logging Host destination must be correct. R2(config)#logging [Destination IP] Troubleshooting Router# show logging Check Syslog server Ping Syslog Server for Troubleshooting Connectivity Check Routing Table Troubleshoot NTP Check for Interface and its line protocol to be up connected with NTP server Check if NTP authentication is enabled Check for NTP password, must be the same Check for the NTP authentication algorithm, Must be the same. Check Routing, Ping the server Update NTP calender. Troubleshoot: Router(config)#ntp update-calendar Router#show clock Router# show ntp status Router# show ntp association Router# show ntp packets Troubleshoot STATIC NAT Static Network Address Translation: Access list must be correctly defined Router# show access-list Router# show running-configuraiton NAT must be applied on interfaces correctly inside and Outside direction Router(config)# int [type] [number] Router(config-if)# ip nat outside Router(config)# int [type] [number] Router(config-if)# ip nat inside Statement Must be correctly Configured Router(config)#ip nat inside source static [Actual IP] [Translated IP] Troubleshooting Router# Show ip nat translation Router# Show ip nat statistics Router# Debug ip nat Dynamic Network Address Translation: Statement Must be correctly Configured R1(config)#ip nat pool [Pool] [Starting IP] [Ending IP] netmask [mask] R1(config)#ip nat inside source list 10 pool [Name] Troubleshooting Router# Show ip nat translation Router# Show ip nat statistics Router# Debug ip nat Port Address Translation: Statement Must be correctly Configured R1(config)#ip nat pool [Pool] [Starting IP] [Ending IP] netmask [mask] R1(config)#ip nat inside source list 10 pool [Name] Overload Troubleshooting Router# Show ip nat translation Router# Show ip nat statistics Router# Debug ip nat
About this Quick Reference Sheet IPSpecialists Quick Reference Sheets are summarized collection of the condensed notes taken from our technology workbooks that are prepared keeping the exam blueprint in mind. It s an ideal handy document to help you remember the most important technology concepts.