Tài liệu Troubleshooting TCP/IP – Show and Debug pptx

SanJose1#show appletalk arp Address Age min Type Hardware Addr Encap Interface 57.76 - Hardware 0010.7b3a.3f60.0000 SNAP Ethernet0 SanJose1# An attempt to type the show ipx arp command w

Trang 1

Lab 4.6.3: Troubleshooting TCP/IP – Show and Debug

#2

#1

192.168.1.10 192.168.2.10

Objective

There are many commands that are useful for troubleshooting TCP/IP It is likely that you have used some of them in earlier classes In this exercise you will look

at some options, but we will save most commands for later chapters when you are looking at specific protocols This lab covers:

• show commands

• debug commands

Warning: The debug command because of its heavy use of CPU cycles can be devastating to a production router’s performance It is possible that a command such as debug IP packet running, during a moderate to heavy traffic period could literally consume all CPU cycles and effectively stop routing, resulting in discarded frames This discussion is included primarily as a tool to help you visualize how and why certain network processes occur We will also look at options that can reduce the impact of the debug commands

Scenario

You have been asked to consult on a small network and offer suggestions on how performance might be improved You are gathering information about the network

Note: The configuration file used for this lab will be used for other module 4 labs,

so please do not change any configuration settings The configuration contains several components for testing purposes and is not intended to represent a good production configuration

Trang 2

If the lab is done in pairs, each person can run the lab steps each may get

slightly different results It might be beneficial to coordinate your efforts and

compare results

Step 1

Cable the lab as shown in the diagram

Load the configuration files SanJose1Config.txt and

Lab4-6-3-SanJose2Config.txt into the appropriate routers

Configure the workstations as follows (same as the last lab):

IP Address: 192.168.1.10 IP Address: 192.168.2.10

Subnet mask: 255.255.255.0 Subnet mask: 255.255.255.0

Default Gateway: 192.168.1.1 Default Gateway: 192.168.2.1

Step 2

The show ip access-list and clear ip access-list counters

commands

On either router type show ip access-list and look over the results You may notice a message indicating matches after some entries like those

highlighted below:

SanJose1#show ip access-list

Standard IP access list 50

deny 192.168.60.0, wildcard bits 0.0.0.255

permit any

Extended IP access list 100

deny tcp any 192.168.90.0 0.0.0.255 eq www

deny tcp any 192.168.90.0 0.0.0.255 eq ftp

deny icmp any host 192.168.60.1

permit ip any any (8571 matches)

Extended IP access list protect_acctg_servers

deny tcp 192.168.60.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.70.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.80.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.90.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.91.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

SanJose1#

These “matches” messages indicate the results of the access list since the last time the counters were cleared or the router rebooted The clear ip

access-list counters command can be used to clear the counters Try it You may find that like the following example a routing update or some other activity immediately started the counters again

SanJose1#clear ip access-list counters

SanJose1#show ip access-list

Trang 3

Standard IP access list 50

permit any

Extended IP access list 100

deny icmp any host 192.168.60.1

permit ip any any

Extended IP access list protect_acctg_servers

deny tcp 192.168.60.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.70.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.80.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.90.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

deny tcp 192.168.91.0 0.0.0.255 192.168.10.0 0.0.0.7 eq www

SanJose1#

Step 3

The show ip arp command

Type the show ip arp command and look over the results Notice that only the LAN interfaces and any hosts connected to them appear in the ARP table You also get the MAC address, encapsulation type, and the local interface to which the address has been mapped There is a show arp command that seems to yield the same result

SanJose1#show ip arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 192.168.1.10 1 00a0.cc23.fe40 ARPA Ethernet0

Internet 192.168.1.1 - 0010.7b3a.3f60 ARPA Ethernet0

Internet 192.168.4.1 - 0010.7b3a.3f60 ARPA Ethernet0

SanJose1#

Type the show appletalk arp command and look over the results You

should only get a single entry unless you have attached some Mac hosts

SanJose1#show appletalk arp

Address Age (min) Type Hardware Addr Encap Interface

57.76 - Hardware 0010.7b3a.3f60.0000 SNAP Ethernet0

SanJose1#

An attempt to type the show ipx arp command will remind you that IPX does not use ARP

Step 4

The show ip route command

Type the show ip route command to display the IP route table Because of a series of loopback addresses and a variety of protocols configured on both

routers, you should see a pretty extensive display Note that on SanJose1 there

are some EX - EIGRP external and IA - OSPF inter area routes

SanJose1#show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

Trang 4

* - candidate default, U - per-user static route, o - ODR

P - periodic downloaded static route

Gateway of last resort is not set

R 192.168.91.0/24 [120/1] via 192.168.0.2, 00:00:21, Serial0

R 192.168.90.0/24 [120/1] via 192.168.0.2, 00:00:21, Serial0

C 192.168.30.0/24 is directly connected, Loopback2

D EX 192.168.60.0/24 [170/2297856] via 192.168.0.2, 05:49:49, Serial0

192.168.95.0/32 is subnetted, 1 subnets

O IA 192.168.95.1 [110/65] via 192.168.0.2, 05:49:49, Serial0

C 192.168.4.0/24 is directly connected, Ethernet0

D 192.168.80.0/24 [90/2297856] via 192.168.0.2, 05:49:49, Serial0

O IA 192.168.96.1 [110/65] via 192.168.0.2, 05:49:50, Serial0

C 192.168.0.0/24 is directly connected, Serial0

C 192.168.1.0/24 is directly connected, Ethernet0

R 192.168.2.0/24 [120/1] via 192.168.0.2, 00:00:24, Serial0

D EX 192.168.70.0/24 [170/2297856] via 192.168.0.2, 05:49:51, Serial0

R 192.168.3.0/24 [120/1] via 192.168.0.2, 00:00:24, Serial0

SanJose1#

Type the show ip route summary command to see the routes summarized plus overhead and bytes used Note that it also provides an additional summary

of OSPF network information

SanJose1#show ip route summary

IP routing table name is Default-IP-Routing-Table(0)

Route Source Networks Subnets Overhead Memory (bytes)

connected 8 0 416 1120

static 0 0 0 0

eigrp 90 3 0 156 420

ospf 100 0 2 104 280

Intra-area: 0 Inter-area: 2 External-1: 0 External-2: 0

rip 4 0 208 560

igrp 90 0 0 0 0

internal 2 2320

Total 17 2 884 4700

Type the show ip route ? command to see the parameter options available Adding parameters like connected, static, or the routing protocols filters the

output

SanJose1#show ip route ?

bgp Border Gateway Protocol (BGP)

connected Connected

egp Exterior Gateway Protocol (EGP)

eigrp Enhanced Interior Gateway Routing Protocol (EIGRP)

igrp Interior Gateway Routing Protocol (IGRP)

isis ISO IS-IS

list IP Access list

mobile Mobile routes

odr On Demand stub Routes

ospf Open Shortest Path First (OSPF)

profile IP routing table profile

rip Routing Information Protocol (RIP)

static Static routes

summary Summary of all routes

supernets-only Show supernet entries only

traffic-engineering Traffic engineered routes

vrf Display routes from a VPN Routing/Forwarding instance

| Output modifiers

<cr>

Trang 5

Type the following commands: show ip route eigrp , show ip route ospf , and show ip route rip to see that you can be selective about what is displayed

SanJose1#show ip route eigrp

D EX 192.168.60.0/24 [170/2297856] via 192.168.0.2, 05:55:25, Serial0

D 192.168.80.0/24 [90/2297856] via 192.168.0.2, 05:55:25, Serial0

D EX 192.168.70.0/24 [170/2297856] via 192.168.0.2, 05:55:25, Serial0

SanJose1#

SanJose1#show ip route ospf

O IA 192.168.95.1 [110/65] via 192.168.0.2, 05:55:38, Serial0

O IA 192.168.96.1 [110/65] via 192.168.0.2, 05:55:38, Serial0

SanJose1#

SanJose1#show ip route rip

R 192.168.91.0/24 [120/1] via 192.168.0.2, 00:00:23, Serial0

R 192.168.90.0/24 [120/1] via 192.168.0.2, 00:00:23, Serial0

R 192.168.2.0/24 [120/1] via 192.168.0.2, 00:00:23, Serial0

R 192.168.3.0/24 [120/1] via 192.168.0.2, 00:00:23, Serial0

SanJose1#

Type the show ip route address command for a host or network address

on the other router to see the source and detail information about that route

SanJose1#show ip route 192.168.2.51

Routing entry for 192.168.2.0/24

Known via "rip", distance 120, metric 1

Redistributing via rip

Last update from 192.168.0.2 on Serial0, 00:00:01 ago

Routing Descriptor Blocks:

* 192.168.0.2, from 192.168.0.2, 00:00:01 ago, via Serial0

Route metric is 1, traffic share count is 1

SanJose1#

Step 5

The show ip interface command

Type the show ip interface command to display the IP interfaces While the command displays all interfaces, let’s look at the LAN interface Not only can we see the IP address, but we see that a second IP address has been assigned to the interface (192.168.4.1/24) We can see that there are both inbound and outbound access lists implemented – we would refer back to our show ip

access-list to see what they do Finally, the Multicast reserved group

(224.0.0.9) tells us that this interface participates in RIP version 2 routing

updates

SanJose1#show ip interface

Ethernet0 is up, line protocol is up

Internet address is 192.168.1.1/24

Broadcast address is 255.255.255.255

Address determined by setup command

MTU is 1500 bytes

Helper address is not set

Directed broadcast forwarding is disabled

Secondary address 192.168.4.1/24

Multicast reserved groups joined: 224.0.0.9

Outgoing access list is 50

Inbound access list is 100

Proxy ARP is enabled

Security level is default

Split horizon is enabled

ICMP redirects are always sent

ICMP unreachables are always sent

Trang 6

ICMP mask replies are never sent

IP fast switching is enabled

IP fast switching on the same interface is disabled

IP Flow switching is disabled

IP Feature Fast switching turbo vector

IP multicast fast switching is enabled

IP multicast distributed fast switching is disabled

Router Discovery is disabled

IP output packet accounting is disabled

IP access violation accounting is disabled

TCP/IP header compression is disabled

RTP/IP header compression is disabled

Probe proxy name replies are disabled

Policy routing is disabled

Network address translation is disabled

WCCP Redirect outbound is disabled

WCCP Redirect exclude is disabled

BGP Policy Mapping is disabled

SanJose1#

Using the same skills, we can see that Loopback 2 is participating in OSPF while Loopback 3 is participating in EIGRP SanJose2 should have a similar variety of routing protocols

Loopback2 is up, line protocol is up

MTU is 1514 bytes

Multicast reserved groups joined: 224.0.0.5 224.0.0.6

MTU is 1514 bytes

Multicast reserved groups joined: 224.0.0.10

Outgoing access list is not set

Make sure that you know the difference between the show ip interface

command and the show interface command As you saw in the examples the

show ip interface command displays the status of features and options on the interface The show interface command includes the MAC address and a variety of performance counters that can be used to gauge the device’s usage For example, the sample data below shows both the input and output statistics It also shows that the queuing strategy is FIFO (first in / first out)

SanJose1#show interface

Hardware is Lance, address is 0010.7b3a.3f60 (bia 0010.7b3a.3f60)

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:12, output 00:00:04, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

413 packets input, 98679 bytes, 0 no buffer

Trang 7

Received 294 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 input packets with dribble condition detected

766 packets output, 73002 bytes, 0 underruns

0 output errors, 0 collisions, 4 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Step 6

The show ip protocols command

Type the show ip protocols command to display the supported protocols While the command displays all protocols, let’s look at the OSPF The command displays the process ID (100), the networks using OSPF and the Administrative Distance

SanJose1#show ip protocols

Routing Protocol is "ospf 100"

Sending updates every 0 seconds

Invalid after 0 seconds, hold down 0, flushed after 0

Outgoing update filter list for all interfaces is

Incoming update filter list for all interfaces is

Redistributing: ospf 100

Routing for Networks:

192.168.0.0

192.168.10.0

192.168.20.0

192.168.30.0

Routing Information Sources:

Gateway Distance Last Update

192.168.96.1 110 06:20:51

Distance: (default is 110)

The IGRP output displays the AS number (90), the network using IGRP, that it is redistributing EIGRP, the various timers and the Administrative Distance The IGRP metric weights show that the metric has not been modified

Routing Protocol is "igrp 90"

Sending updates every 90 seconds, next due in 28 seconds

Default networks flagged in outgoing updates

Default networks accepted from incoming updates

IGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0

IGRP maximum hopcount 100

IGRP maximum metric variance 1

Redistributing: igrp 90, eigrp 90

192.168.50.0

The EIGRP output displays the AS number (90), the networks using EIGRP, that

it is redistributing IGRP, that automatic address summarization is on, the various timers and both Administrative Distance The IGRP metric weights show that the metric has not been modified

Routing Protocol is "eigrp 90"

Default networks flagged in outgoing updates

Default networks accepted from incoming updates

Trang 8

EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0

EIGRP maximum hopcount 100

EIGRP maximum metric variance 1

Redistributing: igrp 90, eigrp 90

Automatic network summarization is in effect

Automatic address summarization:

192.168.0.0/24 for Ethernet0, Loopback0, Loopback1

Loopback2, Loopback3, Loopback4

192.168.40.0/24 for Ethernet0, Loopback0, Loopback1

Loopback2, Loopback4, Serial0

192.168.0.0

192.168.40.0

192.168.0.2 90 06:20:55

Distance: internal 90 external 170

The RIP output displays the networks using RIP, that version 2 is being used, the various timers and the Administrative Distance The IGRP metric weights show that the metric has not been modified

Routing Protocol is "rip"

Sending updates every 30 seconds, next due in 24 seconds

Redistributing: rip

Default version control: send version 2, receive version 2

Interface Send Recv Triggered RIP Key-chain

Ethernet0 2 2

Serial0 2 2

192.168.0.0

192.168.1.0

Interface Send Recv Triggered RIP Key-chain

192.168.4.0

192.168.0.2 120 00:00:25

Note there is no similar command for either AppleTalk or IPX

Step 7

The show protocols command

Type the show protocols command to summarize each interface and the

network protocols associated with them There is a Global values: summary of

all network protocols enabled on the router

SanJose1#show protocols

Global values:

Internet Protocol routing is enabled

Appletalk routing is enabled

IPX routing is enabled

AppleTalk address is 57.76, zone A

IPX address is 30.0010.7b3a.3f60

IPX address is 31.0000.1111.1111

IPX address is 32.0000.1111.1111

Trang 9

IPX address is 33.0000.1111.1111

Serial0 is up, line protocol is up

AppleTalk address is 18.153, zone A

IPX address is 20.0000.1111.1111

Serial1 is administratively down, line protocol is down

SanJose1#

Step 8

The show ip traffic command

Type the show ip traffic command to summarize IP protocol activity since the last clear command or the router rebooted The IP statistics summarizes the broadcast and multicast activity as well as revealing that there were

encapsulation failures

SanJose1#show ip traffic

IP statistics:

Rcvd: 50588 total, 20545 local destination

0 format errors, 0 checksum errors, 1 bad hop count

0 unknown protocol, 0 not a gateway

0 security failures, 0 bad options, 0 with options

Opts: 0 end, 0 nop, 0 basic security, 0 loose source route

0 timestamp, 0 extended security, 0 record route

0 stream ID, 0 strict source route, 0 alert, 0 cipso

0 other

Frags: 0 reassembled, 0 timeouts, 0 couldn't reassemble

0 fragmented, 0 couldn't fragment

Bcast: 2403 received, 378 sent

Mcast: 13923 received, 15700 sent

Sent: 21297 generated, 26539 forwarded

Drop: 10 encapsulation failed, 0 unresolved, 0 no adjacency

555 no route, 0 unicast RPF, 0 forced drop

Type the ICMP statistics will vary depending on whether you did the ping and

trace exercises during this session

ICMP statistics:

Rcvd: 0 format errors, 0 checksum errors, 0 redirects, 4 unreachable

2891 echo, 15 echo reply, 16 mask requests, 0 mask replies, 0 quench

0 parameter, 0 timestamp, 0 info request, 0 other

8 irdp solicitations, 0 irdp advertisements

Sent: 0 redirects, 262 unreachable, 22 echo, 2831 echo reply

0 mask requests, 0 mask replies, 0 quench, 0 timestamp

0 info reply, 0 time exceeded, 0 parameter problem

0 irdp solicitations, 0 irdp advertisements

UDP statistics:

Rcvd: 3051 total, 1263 checksum errors, 1787 no port

Sent: 2723 total, 0 forwarded broadcasts

TCP statistics:

Rcvd: 1343 total, 0 checksum errors, 0 no port

Sent: 2104 total

Probe statistics:

Rcvd: 0 address requests, 0 address replies

0 proxy name requests, 0 where-is requests, 0 other

Sent: 0 address requests, 0 address replies (0 proxy)

0 proxy name replies, 0 where-is replies

Trang 10

EGP statistics:

Rcvd: 0 total, 0 format errors, 0 checksum errors, 0 no listener

Sent: 0 total

IGRP statistics:

Rcvd: 0 total, 0 checksum errors

Sent: 303 total

OSPF statistics:

Rcvd: 2508 total, 0 checksum errors

2446 hello, 3 database desc, 0 link state req

14 link state updates, 14 link state acks

Sent: 2477 total

IP-IGRP2 statistics:

Rcvd: 10577 total

Sent: 10580 total

PIMv2 statistics: Sent/Received

Total: 0/0, 0 checksum errors, 0 format errors

Registers: 0/0, Register Stops: 0/0, Hellos: 0/0

Join/Prunes: 0/0, Asserts: 0/0, grafts: 0/0

Bootstraps: 0/0, Candidate_RP_Advertisements: 0/0

IGMP statistics: Sent/Received

Total: 0/0, Format errors: 0/0, Checksum errors: 0/0

Host Queries: 0/0, Host Reports: 0/0, Host Leaves: 00

DVMRP: 0/0, PIM: 0/0

ARP statistics:

Rcvd: 351 requests, 0 replies, 0 reverse, 0 other

Sent: 0 requests, 10 replies (0 proxy), 29 reverse

SanJose1#

Step 9

The show cdp neighbor [detail] command

Type the show cdp neighbor command to use the Cisco Discovery Protocol

to gather information on adjacent devices The lab output should show a router

on one side and a switch on the other Keep in mind that only Cisco devices will

be detected

SanJose1# show cdp neighbors

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID

Switch Eth 0 143 T S WS-C2924M-Fas 0/22

SanJose2 Ser 0 164 R 2524 Ser 0

SanJose1#

Type the show cdp neighbor detail command to get a more in depth view

of the neighbor devices In the following output we see that the unnamed switch

is a model 2924M-XL running version 12.0(5) of the IOS The router SanJose2 is

a 2524 running version 12.0(5)T of the IOS and is configured to support IP,

Novell, and Appletalk We also have one interface address for each protocol

SanJose1# show cdp neighbors detail

-

Device ID: Switch

Entry address(es):

Platform: cisco WS-C2924M-XL, Capabilities: Trans-Bridge Switch

Interface: Ethernet0, Port ID (outgoing port): FastEthernet0/22

Holdtime : 136 sec

Tiêu đề	Troubleshooting TCP/IP – Show and Debug
Chuyên ngành	Internetwork Troubleshooting
Thể loại	Lab
Năm xuất bản	2001

Định dạng
Số trang	16
Dung lượng	55,52 KB