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Community Member

Strange Lan Problem --HELP

In my company, we have a Core-Layer3 switch, and configured the netwrok into some VLANs.

There is a new computer installed with 2 NICs,one ip is set to VLAN2 (192.168.1.79/24), and another is set

to VLAN100(192.168.100.79/24) and all the VLAN setting on switch is correct.

In my office ,I could ping 192.168.1.79, but i couldn't ping 192.168.100.79, but i could ping 192.168.100.9

(another computer),and on computer 192.168.100.9 I could ping 192.168.100.79...

The Trace information as following,(192.168.1.35 is core layer3 switch)

The IP of tracing computer I used to trace is 192.168.1.170 (VLAN2)

Tracing route to monitor.bbb.com [192.168.100.9]

over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms sha_h_td7172.bbb.com [192.168.1.35]

2 <1 ms <1 ms <1 ms monitor.bbb.com [192.168.100.9]

Trace complete.

C:\Documents and Settings\sheldonwu>tracert 192.168.100.79

Tracing route to 192.168.100.79 over a maximum of 30 hops

1 <1 ms <1 ms <1 ms sha_h_td7172.bbb.com [192.168.1.35]

2 * * * Request timed out.

3 * * * Request timed out.

4 * * * Request timed out.

5 * ^C

C:\Documents and Settings\sheldonwu>

Core Layer3 Switch Routing as follwing.

C 192.168.241.0/24 is directly connected, Vlan241

C 192.168.247.0/24 is directly connected, Vlan52

C 192.168.246.0/24 is directly connected, Vlan51

C 192.168.200.0/24 is directly connected, Vlan200

C 192.168.1.0/24 is directly connected, Vlan2

C 192.168.100.0/24 is directly connected, Vlan100

S* 0.0.0.0/0 [1/0] via 192.168.1.10

C 192.168.242.0/23 is directly connected, Vlan70

C 192.168.244.0/23 is directly connected, Vlan60

And I could ping 192.168.100.79 on Core Layer3 Switch...

Could someone tell me the reason ?? ....

1 ACCEPTED SOLUTION

Accepted Solutions
Community Member

Re: Strange Lan Problem --HELP

the reason you could ping 192.168.1.79 is because it is configured with a gateway.

the reson you could ping 192.168.100.79 from 192.168.100.9 is because they are on the same subnet, 100.9 doesn't need to go through a gateway to get to 100.79.

the reason you could not ping 192.168.100.79 from other vlans is because the nic with the 100.79 ip doesn't have a gateway configured.

the reason you could not configure 100.9 with a gateway is because windows doesn't allow 2 nic's with both configured with a gateway

13 REPLIES
Community Member

Re: Strange Lan Problem --HELP

You are not able to ping 192.168.100.79 from the new computer right but you are able to ping other hosts in that subnet.

Have you configured both interfaces of PC with gateways of their vlan IP.

Regards,

Suresh Jain

Community Member

Re: Strange Lan Problem --HELP

Yes, I configured, I don't konw why in the same subnet I just could ping one....

Community Member

Re: Strange Lan Problem --HELP

Is it possible for you paste the switch config.

Re: Strange Lan Problem --HELP

Hi There,

Have you enabled the NIC Teaming on the PC ?

What happens if you disconnect the other link 192.168.1.79. Can you reach 192.168.100.79 ?

Can other PC in the same Vlan 100 ping 192.168.10.79?

Post the switch config.

-amit singh

Community Member

Re: Strange Lan Problem --HELP

If I disconnect the 192.168.1.79, I still couldn't ping the 192.168.100.79. And Vlan100's computer could ping 192.168.100.79

So ...very strange...

Community Member

Re: Strange Lan Problem --HELP

Hi

Is it a windows PC, if yes then give route print in the command prompt. Please post the output.

Community Member

Re: Strange Lan Problem --HELP

My L3 Switch configuration as following: (Part1)

SW-7F-CORE01#show run

Building configuration...

Current configuration : 7699 bytes

!

! Last configuration change at 01:43:10 UTC Thu Nov 9 2006

! NVRAM config last updated at 03:36:21 UTC Fri Oct 13 2006

!

version 12.2

no service pad

service timestamps debug uptime

service timestamps log uptime

service password-encryption

service compress-config

!

hostname SW-7F-CORE01

!

boot-start-marker

boot-end-marker

!

enable secret xxx

!

no aaa new-model

ip subnet-zero

no ip domain-lookup

ip domain-name bbb.com

ip name-server 192.168.1.43

!

no ip dhcp snooping information option

ip dhcp-server 192.168.1.43

!

no file verify auto

!

spanning-tree mode pvst

spanning-tree extend system-id

spanning-tree vlan 2,51,70,200,241 priority 24576

spanning-tree vlan 52,60,100,500 priority 28672

power redundancy-mode redundant

!

!

!

vlan internal allocation policy ascending

!

interface Port-channel1

description Etherchannel_To_sha-6f-C4948-L3-sw02

switchport

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/1

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/2

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/3

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/4

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/5

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/6

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/7

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/8

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/9

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/10

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/11

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/12

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/13

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/14

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/15

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/16

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/17

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/18

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/19

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/20

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/21

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/22

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/23

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/24

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/25

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/26

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/27

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/28

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/29

switchport trunk encapsulation dot1q

switchport mode trunk

!

Community Member

Re: Strange Lan Problem --HELP

(Part2)

interface GigabitEthernet1/30

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/31

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/32

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/33

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/34

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/35

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/36

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/37

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/38

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/39

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/40

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/41

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/42

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/43

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 1 mode on

!

interface GigabitEthernet1/44

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 1 mode on

!

interface GigabitEthernet1/45

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/46

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/47

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/48

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface Vlan1

no ip address

shutdown

!

interface Vlan2

ip address 192.168.1.58 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

standby 2 ip 192.168.1.3

standby 2 priority 110

standby 2 preempt

!

interface Vlan51

ip address 192.168.246.2 255.255.255.0

ip helper-address 192.168.1.43

no ip redirects

no ip unreachables

no ip proxy-arp

standby 51 ip 192.168.246.1

standby 51 priority 110

standby 51 preempt

!

interface Vlan52

ip address 192.168.247.2 255.255.255.0

ip helper-address 192.168.1.43

no ip redirects

no ip unreachables

no ip proxy-arp

standby 52 ip 192.168.247.1

standby 52 priority 90

standby 52 preempt

!

interface Vlan60

ip address 192.168.244.2 255.255.254.0

ip helper-address 192.168.1.43

no ip redirects

no ip unreachables

no ip proxy-arp

standby 60 ip 192.168.244.1

standby 60 priority 90

standby 60 preempt

!

interface Vlan70

ip address 192.168.242.2 255.255.254.0

ip helper-address 192.168.1.43

no ip redirects

no ip unreachables

no ip proxy-arp

standby 70 ip 192.168.242.1

standby 70 priority 110

standby 70 preempt

!

interface Vlan100

ip address 192.168.100.17 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

standby 100 ip 192.168.100.1

standby 100 priority 90

standby 100 preempt

!

interface Vlan200

ip address 192.168.200.18 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

standby 200 ip 192.168.200.1

standby 200 priority 110

standby 200 preempt

!

interface Vlan241

ip address 192.168.241.1 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

!

ip route 0.0.0.0 0.0.0.0 192.168.1.10

ip http server

!

!

banner login ^C

^C

!

line con 0

exec-timeout 30 0

stopbits 1

line vty 0 4

exec-timeout 20 0

password 7 0832584B051504

login

line vty 5 15

exec-timeout 5 0

password 7 05080F1C2243

login

!

end

SW-7F-CORE01#

Community Member

Re: Strange Lan Problem --HELP

Ooh~ when I down the 192.168.1.79~~and another ip could be ping... Maybe it's so called teaming ...But how could I disable it?

The os I used is Debian(sarge), Thanks.

Community Member

Re: Strange Lan Problem --HELP

But when the two NICs are up ,VLAN100 could ping the 192.168.100.79..... And on this computer, I only set the gateway 192.168.100.1, configuration is following:

Kernel IP routing table

Destination Gateway Genmask Flags Metric Ref Use Iface

localnet * 255.255.255.0 U 0 0 0 eth0

localnet * 255.255.255.0 U 0 0 0 eth2

default 192.168.100.1 0.0.0.0 UG 0 0 0 eth0

with it, I could ping other VLAN's computer.

Community Member

Re: Strange Lan Problem --HELP

Could any one help me ??

Community Member

Re: Strange Lan Problem --HELP

the reason you could ping 192.168.1.79 is because it is configured with a gateway.

the reson you could ping 192.168.100.79 from 192.168.100.9 is because they are on the same subnet, 100.9 doesn't need to go through a gateway to get to 100.79.

the reason you could not ping 192.168.100.79 from other vlans is because the nic with the 100.79 ip doesn't have a gateway configured.

the reason you could not configure 100.9 with a gateway is because windows doesn't allow 2 nic's with both configured with a gateway

Re: Strange Lan Problem --HELP

In response to the above post, if you want the connectivity you could add a route on the machine with dual nic

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