logging on

dargspurNetworking and Communications

Oct 27, 2013 (3 years and 11 months ago)

146 views

校園網路與
Cisco
網路設備

故障排除簡介

麟瑞科技

張晃崚

Router Functions


Routing = building
maps and giving
directions


Switching = moving
packets between
interfaces

Switching Vs.

Path Determination

Network
-
Layer

Routing Protocol

Handles Path

Determination

Packet

Switching


Routers are packet relays or switches


Path determination is overhead

Routing Table

One Forwarding Table

198.113.181.0

[170/304793]

192.150.42.177

02:03:50

D

198.113.178.0

192.168.96.0

192.168.97.0

[110/9936]

192.150.42.177

02:03:50

O

192.150.42.177

00:00:20

R

C

[120/3]

Ethernet0

Ethernet0

Ethernet0

Ethernet0

Age

Source

Network #

Interface

Next Hop

Metric

Building the Routing Table


Hardware state


Static

Routes are manually defined


Dynamic

Routes are learned from a
protocol

Apply Cisco IOS Software
Troubleshooting Tools


show

commands

snapshot problems with interfaces,
media, or network performance


debug

commands

check the flow of protocol traffic
for problems, protocol bugs, or misconfigurations


ping

commands

test the reachability of a protocol on
a targeted remote router or other device


trace

commands

determine a step
-
by
-
step routing
path to remote routers or other devices

Understanding the Output of
Diagnostic Commands


Understand basic router architecture and processes

Switching


processes

Routing


processes

ATM

show buffers

show controllers


trace

debug

show interfaces

ping

Why Handle the Impact of Cisco
Troubleshooting Tools?


You need tools that diagnose the targeted protocol behavior
to troubleshoot network problems


Understanding troubleshooting output requires an
understanding of router architecture and processes


Some diagnostic or control resources come at the expense of
processing and switching efficiency


Selective and temporary use of tools can minimize the impact
of these tools on router performance


To balance troubleshooting needs and router efficiency, you
must operate the tools correctly

Cisco Router Routing Processes and
Switching Processes


Routing functions
identify the best path to
a destination over an
interface



Switching types
function to move the
packets, frames, or cells
themselves

Understand the two different processes:

Routing Process

101

102

103

106

105

104

A

B

ATM

C

D

Routing Process

101

102

103

106

105

Update

Update

Update

Update

104

A

B

ATM

C

D

Update

Routing Process

101

102

103

106

105

Update

Update

Update

Update

104

A

B

ATM

C

D

Update

Destination Network

101

102

103

104

105

106

Routing Table of Router B

Reachable Interface

FDDI 0/0

FDDI 0/0

Ethernet 1/0

ATM 2/0

ATM 2/0

ATM 2/0

Switching Process

102

103

104

Packet

ETHERNET

HEADER

ATM

B

Switching Process

102

103

104

ETHERNET

HEADER

Destination Network

101

102

103

104

105

106

Routing Table of Router B

Reachable Interface

FDDI 0/0

FDDI 0/0

Ethernet 1/0

ATM 2/0

ATM 2/0

ATM 2/0

ATM

B

Data

Packet

Switching Process

102

103

104

ETHERNET

HEADER

FDDI

HEADER

Destination Network

101

102

103

104

105

106

Routing Table of Router B

Reachable Interface

FDDI 0/0

FDDI 0/0

Ethernet 1/0

ATM 2/0

ATM 2/0

ATM 2/0

ATM

B

Data

Packet

Packet

The Route Processor Handles
Broadcasts and Special Processes

FFFF.FFFF.FFFF



Debug filtering



Error logging to syslog



SNMP

Route Processor

Keepalives



Protocol translations



Tunnel maintenence



Special queuing


Special processes like diagnostic or control functions come at
the expense of processing and switching efficiency

Handling the Cisco IOS
debug

Troubleshooting Tool


Be aware of its process switching implications


Use to isolate problems, not to monitor network


Focus scope of
debug

command with arguments


Limit impact of checking with access lists


Undo the
debug

after troubleshooting

debug

Commands Use Process Switching

1. Initialization with process switching

Switching Types

2. Faster switching for
subsequent packets

Fast Switching

Optimum Switching

Autonomous Switching

Silicon Switching

3. Problem diagnosis requires
troubleshooting tools

4.
debug

commands
use

process switching

Using the Cisco IOS
debug

Command



The command
service timestamps

adds time stamps to debug output



Do not use
debug all
; focus debug with specific arguments



Use
terminal monitor

to see debug output from a Telnet terminal



Consider debugging events, rather than debugging packets



When you can, apply an access control list to filter
debug

Suggestions from
debug

users:

Using an Access List with
debug



Capability for constraining focus of debug command in IP



With an extended access list, you can specify source and destination



Specify an optional IP protocol or protocol port number



Remove access list and undebug when finished

access
-
list 101 extended

permit tcp any host 172.16.4.20 eq telnet established

interface ether 1

ip access
-
group 101

end



debug ip packet detail

telnet 172.16.4.20


Undo
debug

after Troubleshooting



Use the
no debug [argument}
command to turn off a specific debug



Use
undebug all
or

no debug all
command to turn off all debugging



Turn off all debugging when you are finished troubleshooting



Configure the router to restore any faster switching type


router#

debug broadcast

Ethernet0: Broadcast ARPA, src 0000.0c00.6fa4, dst ffff.ffff.ffff, type 0x0800,

data 4500002800000000FF11EA7B, len 60

Serial3: Broadcast HDLC, size 64, type 0x800, flags 0x8F00

Serial2: Broadcast PPP, size 128

Serial7: Broadcast FRAME
-
RELAY, size 174, type 0x800, DLCI 7a

router#

undebug all

All debugging has been turned off

router#

Error Message Logging



terminal monitor

Syslog Server

Console

Console

Error Message Logging

logging on

(default)



terminal monitor

Syslog Server

Console

Console

Error Message Logging

logging console




terminal monitor

Syslog Server

Console

Console

logging on

(default)

Error Message Logging

logging console




terminal monitor

Syslog Server

Console

Console

logging buffered

(default)

logging on

(default)

Error Message Logging

logging console




terminal monitor

Syslog Server

Console

Console

logging monitor

logging buffered

(default)

logging on

(default)

Error Message Logging

logging console




terminal monitor

Syslog Server

Console

Console

logging
ip
-
address

logging monitor

logging buffered

(default)

logging on

(default)

Error Message Logging

logging buffered

(default)

logging on

(default)

logging console




terminal monitor

Syslog Server

Console

Console

logging ip
-
address


logging trap

logging monitor

Limiting the Display of Error Messages

Level Name

Level

Description

Syslog Definition

emergencies

0

System unusable

LOG_EMERG

alerts

1

Immediate action needed

LOG_ALERT

critical

2

Critical conditions

LOG_CRIT

errors

3

Error conditions

LOG_ERR

warnings

4

Warning conditions

LOG_WARNING

notifications

5

Normal but significant condition

LOG_NOTICE

informational

6

Informational messages only

LOG_INFO

debugging

7

Debugging messages

LOG_DEBUG

Level Name

Level Description

Syslog Definition



Use logging console
level

command for console terminal



Use logging monitor
level

command for other terminals



Use logging trap
level

command for syslog server

show logging

Command

Router#
show logging

Syslog logging: enabled


Console logging: disabled


Monitor logging: level debugging, 18 messages logged.


Trap logging: level informational, 18 messages logged.


Logging to 192.31.7.19

SNMP logging: enabled, retransmission after 30 seconds


741 messages logged


Logging to 131.108.1.27, 0/10


Logging to 131.108.1.111, 0/10


Logging to 131.108.2.63, 0/10

Reachability and Step
-
by
-
Step Path Tests

Test reachability:



ping ip



ping ipx



ping appletalk


Test step
-
by
-
step path:



trace


These tests operate in two levels: user mode and
privileged mode

ping

Command (User) IP

Router>

ping fred

Type escape sequence to abort.

Sending 5, 100
-
byte ICMP Echos to 192.31.7.27, timeout is 2 seconds:

!!!!!

Success rate is 100 percent, round
-
trip min/avg/max = 1/3/4 ms

Router>

ping 192.45.3.1

Type escape sequence to abort.

Sending 5, 100
-
byte ICMP Echos to 192.45.3.1, timeout is 2 seconds:

.U.U.

Success rate is 0 percent (0/5)

ping

Command (Privileged) IP

Router#

ping

Protocol [ip]:

Target IP address: fred

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]

Extended commands [n]: y

Source address:

Type of service [0]:

Set DF bit in IP header? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]: r

Number of hops [9]:

Loose, Strict, Record, Timestamp, Verbose[RV]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100
-
byte ICMP Echos to 131.108.1.115, timeout is 2

seconds:

Packet has IP options: Total option bytes=39, padded length=40

Record route: <*> 0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0

0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0

-

More
-

ping

Command (Privileged) IP
(cont.)

-

cont
-

The following display is a detail of the Echo packet section:

0 in 4 ms. Received packet has options

Total option bytes= 40, padded length=40

Record route: 160.89.80.31 131.108.6.10 131.108.1.7 131.108.1.115

131.108.1.115 131.108.6.7 160.89.80.240 160.89.80.31 <*> 0.0.0.0

End of list

1 in 8 ms. Received packet has options

Total option bytes= 40, padded length=40

Record route: 160.89.80.31 131.108.6.10 131.108.1.6 131.108.1.115

131.108.1.115 131.108.6.7 160.89.80.240 160.89.80.31 <*> 0.0.0.0

End of list

:

:

2 in 4 ms. Received packet has options

Total option bytes= 40, padded length=40

Record route: 160.89.80.31 131.108.6.10 131.108.1.7 131.108.1.115

131.108.1.115 131.108.6.7 160.89.80.240 160.89.80.31 <*> 0.0.0.0

End of list

Success rate is 100 percent, round
-
trip min/avg/max = 4/5/8 ms

ping

Command (User) IPX

and AppleTalk

Router>

ping appletalk 1024.128

Type escape sequence to abort.

Sending 5, 100
-
byte AppleTalk Echoes to 1024.128, timeout is 2 seconds:

!!!!!

Success rate is 100 percent, round
-
trip min/avg/max = 4/4/8 ms

Router>

ping ipx 211.0000.0c01.f4cf

Type escape sequence to abort.

Sending 5, 100
-
byte Novell Echoes to 211.0000.0c01.f4cf, timeout is 2

seconds:

•••••

Success rate is 0 percent (0/5)

ping

Command (Privileged) IPX

Router#

ping

Protocol [ip]: ipx

Target Novell Address: 211.0000.0c01.f4cf

Repeat count [5]:

Datagram Size [100]:

Timeout in seconds [2]:

Verbose [n]:

Novell Standard Echo [n]:

Type escape sequence to abort.

Sending 5 100
-
byte Novell echoes to 211.0000.0c01.f4cf, timeout is 2 seconds.

!!!!!

Success rate is 100%, round trip min/avg/max = 1/2/4 ms.

ping
Command (Privileged)
AppleTalk

Router#

ping

Protocol [ip[: appletalk

Target AppleTalk address: 4.129

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Verbose [n]: y

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100
-
byte AppleTalk Echos to 4.129, timeout is 2 seconds:

0 in 4 ms from 4.129 via 1 hop

1 in 8 ms from 4.129 via 1 hop

2 in 4 ms from 4.129 via 1 hop

3 in 8 ms from 4.129 via 1 hop

4 in 8 ms from 4.129 via 1 hop

Success rate is 100 percent, round trip min/avg/max = 4/6/8 ms

trace

Command (User) IP

Router#

trace ip ABA.NYC.mil

Type escape sequence to abort.

Tracing the route to ABA.NYC.mil (26.0.0.73)

1 DEBRIS.CISCO.COM (131.108.1.6) 1000 msec 8 msec 4 msec

2 BARRNET
-
GW.CISCO.COM (131.108.16.2) 8 msec 8 msec 8 msec

3 EXTERNAL
-
A
-
GATEWAY.STANFORD.EDU (192.42.110.225) 8 msec 4 msec 4 msec

4 BB2.SU.BARRNET.NET (131.119.254.6) 8 msec 8 msec 8 msec

5 SU.ARC.BARRNET.NET (131.119.3.8) 12 msec 12 msec 8 msec

6 MOFFETT
-
FLD
-
MB.in.MIL (192.52.195.1) 216 msec 120 msec 132 msec

7 ABA.NYC.mil (26.0.0.73) 412 msec 628 msec 664 msec

trace

Command (Privileged) IP

Router#

trace

Protocol [ip]:

Target IP address: mit.edu

Source address:

Numeric display [n]:

Timeout in seconds [3]:

Probe count [3]:

Minimum Time to Live [1]:

Maximum Time to Live [30]:

Port number[33434]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Type escape sequence to abort.

Tracing the route to MIT.EDU (18.72.2.1)

1 ICM
-
DC
-
2
-
V1.ICP.NET (192.108.209.17) 72 msec 72 msec 88 msec

2 ICM
-
FIX
-
E
-
H0
-
T3.ICP.NET (192.157.65.122) 80 msec 128 msec 80 msec

3 192.203.229.246 540 msec 88 msec 84 msec

4 T3
-
2.WASHINGTON
-
DC
-
CNSS58.T3.ANS.NET (140.222.58.3) 84 msec 116 msec 88 msec

5 T3
-
3.WASHINGTON
-
DC
-
CNSS56.T3.ANS.NET (140.222.56.4) 80 msec 132 msec 88 msec

6 T3
-
0.NEW
-
YORK
-
CNSS32.T3.ANS.NET (140.222.32.1) 92 msec 132 msec 88 msec

7 T3
-
0.HARTFORD
-
CNSS48.T3.ANS.NET (140.222.48.1) 88 msec 88 msec 88 msec

8 T3
-
0.ENSS134.T3.ANS.NET (140.222.134.1) 92 msec 128 msec 92 msec

9 W91
-
CISCO
-
EXTERNAL
-
FDDI.MIT.EDU (192.233.33.1) 92 msec 92 msec 112 msec

10 E40
-
RTR
-
FDDI.MIT.EDU (18.168.0.2) 92 msec 120 msec 96 msec

11 MIT.EDU (18.72.2.1) 96 msec 92 msec 96 msec

Information Needed byTechnical Support

1. General information

Problem history

Problem symptoms

show version


5. Optional information

Debug captures

Protocol analyzer

2. Crash or hang problems

show stack

core dump


4. Loss of functionality

problems

show interfaces

show protocol

show protocol traffic

3. Lost data or performance

problems

show interfaces

show buffer

show memory

show process

show protocol

show protocol traffic

show version

Command

Router>
show version

Cisco Internetwork Operating System Software

IOS (tm) GS Software (GS7
-
K
-
M), Version 11.0(9), RELEASE SOFTWARE (fc1)

Copyright (c) 1986
-
1996 by cisco Systems, Inc.

Compiled Tue 11
-
Jun
-
96 03:52 by tstevens

Image text
-
base: 0x00001000, data
-
base: 0x007614F0


ROM: System Bootstrap, Version 5.2(2), RELEASE SOFTWARE

ROM: GS Software (GS7), Version 10.2(2), RELEASE SOFTWARE (fc1)


Router uptime is 2 days, 20 hours, 26 minutes

System restarted by error
-

Software forced crash, PC 0x1CF82C at 20:25:38 PDT M

on Aug 5 1996

System image file is "images/gs7
-
k
-
mz.110
-
9", booted via flash


cisco RP1 (68040) processor (revision B0) with 16384K bytes of memory.

Processor board ID 00130334

G.703/E1 software, Version 1.0.

Bridging software.

X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.

Primary Rate ISDN software, Version 1.0.

1 Silicon Switch Processor.

1 EIP controller (6 Ethernet).

1 FEIP controller (2 FastEthernet).

6 Ethernet/IEEE 802.3 interfaces.

2 FastEthernet/IEEE 802.3 interfaces.

48 Serial network interfaces.

128 bytes of non
-
volatile configuration memory.

4096K bytes of flash memory sized on embedded flash.


Configuration register is 0x102

Router>

show processes

command

CPU utilization for one minute: 38%; for five minutes: 37%


PID Q T PC Runtime (ms) Invoked uSecs Stacks TTY Process


1 M E 122DE 62812 4897 12826 780/1000 0 Net Background


2 M E 22842 8 19 421 804/1000 0 Logger


809 M E 74AF0 272808 489888 556 1504/2000 36 Exec


4 H E 67C0 373540 630248 592 628/900 0 IP Input


5 M E 3E124 26044 630201 41 824/1000 0 IP Protocols


6 M E 46BA2 592 255178 2 794/1000 0 TCP Timer


7 L E 47CE6 1736 1635 1061 776/1000 0 TCP Protocols


8 L E 67C0 0 1 0 958/1000 0 ARP Input


813 M * 768 384 93 4129 1456/2000 42 Virtual Exec


10 M E 3F51E 0 1 0 894/1000 0 BOOTP Server


11 H E 67C0 25096 194823 128 426/500 0 Net Input


12 M T 36FA 5420 277303 19 850/1000 0 TTY Background


13 L E 5444E 65996 24907 2649 686/1000 0 SNMP Server


14 M E 6E842 0 1 0 966/1000 0 Serial Line IP

Router#
show processes



Add argument
cpu

to show detailed CPU utilization




Add argument
memory

to show memory usage


Cisco IOS Software Tools and Commands

ping ip
(privileged)

show ip interface

show ip protocols

show ip route

show ip traffic

trace

show ip access
-
list

show ip arp (and clear arp
-
cache)

debug
commands


router#

Console


debug

Commands


Handle
debug

commands appropriately


When you are done with a debug, turn it
off with
no debug
or
undebug all

debug ip eigrp

debug ip icmp

debug ip igrp events

debug ip packet

debug ip packet [access
-
list
-
number]

debug ip rip

debug arp

debug arp

Command


First three output lines indicate normal network behavior


Fourth output line indicates a problem

the router received
an ARP reply for its own address

?

router#

debug arp

IP ARP: sent req src 131.108.22.7 0000.0c01.e117, dst 131.108.22.96 0000.0000.0000

IP ARP: rcvd rep src 131.108.22.96 0800.2010.b908, dst 131.108.22.7

IP ARP: rcvd req src 131.108.6.10 0000.0c00.6fa2, dst 131.108.6.62

IP ARP: rep filtered src 131.108.22.7

080

0.5a36.a4

5

6, dst 255.255.255.25

5

f

fff.ffff.ffff

Problem Isolation in TCP/IP Networks


Isolating a connection problem between a local and remote host

Fix remote host

configuration

Y

Y

N

N

N

Fix any router

configuration problems,

and any LAN problems

Fix any router

configuration problems,

LAN or WAN problems

Local host

configuration OK?

Y

N

Fix any problems

with address,

subnet mask,

default gateway

Can you ping

local router?

Can you reach all

routers to remote

host?

Remote host

configuration OK?

Symptom: Users Can Access Some
Hosts but Not Others


Can host A connect to host C?


Can host A connect to host B?


Can host D connect to host C?

Host D

10.1.2.7

255.255.255.0

Host C

10.1.2.8

255.255.0.0

Host B

10.1.1.6

255.255.0.0

Host A

10.1.1.5

255.255.255.0

Ethernet 1

10.1.2.1

255.255.255.0

Ethernet 0

10.1.1.1

255.255.255.0

subnet 2

subnet 1

Symptom: Users Cannot Connect
When One Redundant Path Is Down

Serial Z

Serial X

Serial Y





B1

C2

C1

Net C1

(Subnet)

Net C2

(Subnet)

Major Network:

Net C

Major Network:

Net B

Use Built
-
In Tools for Troubleshooting



Cisco IOS tools and commands in the router



Catalyst
show

commands in the switch



TCP/IP tools included with Windows

#telnet

Console

and Client

Server

Problem Isolation in Windows NT/95
TCP/IP Networks


Isolating problems with Windows IP connections

Fix any problems with TCP/IP configuration

or address resolution, the Hosts file,


the LMHosts file, WINS, ARP, DNS problems

(or some other Windows networked service)

Y

Y

N

N

Fix any problems
with

router interface,

configuration, or

access lists


Fix any problems with

the IP addressing,

subnetting, default gateway

route table, or ARP cache


Local host

configuration


OK?

Y

N

Fix any problems with local
address, subnet mask,default
gateway, or DHCP setup, and target
addresses

Router


configuration

OK?

N

NT


Server

configuration


OK?

Can you

connect using IP
addresses

?

Symptom: Browser Does Not Show All
Network Resources

Host D

10.1.2.7

255.255.255.0

Master Browser

NT Server C

10.1.2.8

255.255.0.0

Master Browser

Host B

10.1.1.6

255.255.0.0

Host A

10.1.1.5

255.255.255.0

Master Browser

Ethernet 1

10.1.2.1

255.255.255.0

Ethernet 0

10.1.1.1

255.255.255.0

subnet 2

subnet 1

Host B

Host A

Host C

Host A

Host B

TCP/IP Symptoms and Problems

Possible Problems

Host cannot access
offnet hosts through
router

Host cannot access
certain networks
through router

Symptoms

No default gateway specified on local host

Misconfigured subnet mask on local host

Router between hosts is down

No default gateway specified on local host

Misconfigured* access list

Discontiguous network due to poor design or
link failure

* Be aware that the access list might be configured correctly. It might be
intentional that users can access some hosts or networks, but not others.


TCP/IP Symptoms and Problems (cont.)

Possible Problems

Users can access
some hosts, but not
others

Some services are
available, but others
are not

Symptoms

Misconfigured subnet mask or address on
hosts or router

Misconfigured access list

No default gateway specified on remote host

Misconfigured extended access list

Users cannot connect
when one redundant
path is down

Discontiguous network due to link failure

Routing has not converged

Misconfigured access list or other routing
filters

TCP/IP Symptoms and Problems (cont.)

Possible Problems

Router sees duplicate routing
updates and packets

Certain protocols are being
routed, others are not

Router or host cannot reach
certain parts of its own
network

Routing is not working when
redistribution is used

Symptoms

Bridge or repeater in parallel with router

Misconfigured access list

Subnet mask configuration mismatch between
router and host

Misconfigured access list

No default gateway specified

Missing
redistribute

or
default
-
metric

command

Problem with default administrative distance

TCP/IP Problems and Action Plans

Possible Problems

No default gateway
specified on local or
remote host

Misconfigured subnet
mask on local or
remote host or router

Symptoms

Check routing table of host using
netstat
-

rn
command

If there is no default, use the
route add default
address 1
command

where address is IP
address of default gateway

To boot with default gateway already
configured, specify default gateway IP address
in host fild/etc/defaultrouter

Check host files/etc/netmasks and /etc/rc.local

Check host configuration with
ifconfig
-
a

Check router configuration with
show ip
interface

TCP/IP Problems and Action Plans (cont.)

Possible Problems

Router between hosts
is down

Misconfigured access
list or other filter

Symptoms

Ping

outward


until problem area is isolated

Check and fix router configurations

Check and fix intermediate LAN or WAN
problems

Ping and trace to isolate router with
misconfigured list

Check routing table
(show ip route)

Check protocol exchanges (for example,
debug
ip rip
)

Temporarily disable access lists (
no ip access
-
group
), test

Debug access lists that cause problem

TCP/IP Problems and Action Plans (cont.)

Possible Problems

Discontiguous
network due to poor
design or link failure

Routing has not
converged

Symptoms

Check routes and how they are learned (
show
ip route
)

Trace or ping to determine where traffic stops

Fix topology or reassign addressing (assign
segments to same major network)

If backup path exists, assign secondary
address

If discontiguous network due to link failure, fix
link

Check for problems with
show ip route

Windows NT/95 TCP/IP

Problems and Action Plans

Unable to reach target
using an IP address


Isolate problem with ping tests



ping loopback address



ping local IP address



ping Cisco router



ping DNS server



ping default gateway address



ping WINS server



ping remote target address

Use
trace

on the Cisco router and tracert on
the NT system

Problem Facts


Action Plans

Windows NT/95 TCP/IP

Problems and Action Plans (cont.)


Action Plans

No default gateway
specified on local or
remote host

Misconfigured IP
address on local or
remote host or router

Problem Facts

Check routing table of host using
netstat
and

route
commands

If there is no default, use the
route add default
address
command,

where address is IP address
of default gateway

To boot with default gateway already
configured, specify default gateway IP address
in host fild/etc/defaultrouter

Check with network control panel

Check host configuration with
ifconfig

Check router configuration with
show ip route
and host configuration with
route

command

Windows NT/95 TCP/IP Resolution

Problems and Action Plans

Local host can access
remote hosts or
server using an IP
target address but not
using other non
-
IP
addresses or a
NetBIOS name


NBT not set up correctly

DNS configuration wrong

Hosts file incorrect

Incorrect LMHosts file on server

WINS configuration wrong

Winsock proxy incorrect or nonfunctional

Problem Facts


Possible Problems