求助,关于一个VLAN的问题.

donggua0713

请教各位,如下VLAN配置问题,很不解.
如附件中图,switch 1 及 switch 2  两台CISCO 3550 交换机.
在switch 1 上面接了个PC1,该端口分配给VLAN 2.
在switch 2 上面接了个PC2,该端口分配给VLAN 2.
在switch 2 上面接了个PC3,该端口分配给VLAN 6.

在switch 2上面配置了VLAN 6的ip 172.16.4.2/24

在switch 1上面配置了VLAN 2的ip 172.16.8.1/24
                      配置了VLAN 6的ip 172.16.4.1

PC1 和 PC2 都属于VLAN 2 172.16.8.0/24
PC3               属于VLAN 6 172.16.4.0/24

switch 2 配置了一个默认路由: ip route 172.16.8.0 255.255.255.0 172.16.4.1

即:
switch 1 上面有VLAN 2 VLAN 6的ip地址被配置,有一个端口分配给VLAN 2,连接到PC 1,属于172.16.8.0/24网段.
switch 2 上面有VLAN 6            的ip地址被配置,有一个端口分配给VLAN 6,连接到PC 3,属于172.16.4.0/24网段.还有一个端口分配到VLAN 2,连接到PC 2,属于172.16.8.0/24网段.

现在的问题是,如果吧PC3的网关设为172.16.4.1,那么PC3无法ping通VLAN 2的电脑.如果吧PC3的网管设为172.16.4.2,则PC3 可以ping通VLAN 2的电脑,这是为什么?

[ 本帖最后由 donggua0713 于 2009-5-25 17:22 编辑 ]

donggua0713

!
version 12.2
no service pad
service timestamps debug uptime
service timestamps log datetime
service password-encryption
service sequence-numbers
!
hostname HYCCT3750
!
enable secret 5 $1$KHA4$le0Wj9s2sKwuyYzkG0cZP1
!
no aaa new-model
switch 1 provision ws-c3750g-24ts
vtp mode transparent
ip subnet-zero
ip routing
ip domain-name cct.com.hk
!
cluster enable admin 0
!
!
!
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
vlan 2
name vlan2
!
vlan 3
name vlan3
!
vlan 5
name vlan5
!
vlan 6
name vlan6
!
vlan 7
name vlan7
!
vlan 8
name vlan8
!
vlan 9
name vlan9
!
vlan 10
name vlan10
!
!
interface GigabitEthernet1/0/1
switchport trunk allowed vlan 1,2,1002-1005
!
interface GigabitEthernet1/0/2
!
interface GigabitEthernet1/0/3
switchport mode access
!
interface GigabitEthernet1/0/4
switchport access vlan 9
Page 1 of 4
file://C:\Documents and Settings\Administrator\Desktop\cisco\hycct3... 5/23/2009
switchport mode access
!
interface GigabitEthernet1/0/5
switchport access vlan 8
switchport mode access
!
interface GigabitEthernet1/0/6
switchport access vlan 6
switchport mode access
!
interface GigabitEthernet1/0/7
switchport access vlan 7
switchport mode access
!
interface GigabitEthernet1/0/8
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/9
switchport access vlan 5
!
interface GigabitEthernet1/0/10
switchport access vlan 5
!
interface GigabitEthernet1/0/11
switchport access vlan 10
switchport trunk allowed vlan 1,5,1002-1005
switchport mode access
!
interface GigabitEthernet1/0/12
switchport access vlan 10
switchport trunk allowed vlan 1,5,1002-1005
switchport mode access
!
interface GigabitEthernet1/0/13
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/14
switchport access vlan 3
switchport mode access
!
interface GigabitEthernet1/0/15
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/16
switchport access vlan 3
switchport mode access
!
interface GigabitEthernet1/0/17
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/18
switchport access vlan 3
switchport mode access
!
interface GigabitEthernet1/0/19
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/20
switchport access vlan 3
Page 2 of 4
file://C:\Documents and Settings\Administrator\Desktop\cisco\hycct3... 5/23/2009
switchport trunk encapsulation dot1q
switchport mode access
!
interface GigabitEthernet1/0/21
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/22
switchport access vlan 3
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/0/23
switchport access vlan 2
switchport mode access
!
interface GigabitEthernet1/0/24
switchport access vlan 3
switchport mode access
!
interface GigabitEthernet1/0/25
switchport access vlan 3
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/0/26
switchport access vlan 3
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/0/27
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/0/28
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface Vlan1
ip address 193.254.18.1 255.255.255.0
!
interface Vlan2
ip address 172.16.8.1 255.255.252.0
!
interface Vlan3
ip address 192.168.100.251 255.255.255.0
!
interface Vlan5
ip address 192.168.18.1 255.255.255.0
!
interface Vlan6
ip address 172.16.4.1 255.255.252.0
!
interface Vlan7
ip address 172.16.12.1 255.255.252.0
!
interface Vlan8
ip address 172.16.2.1 255.255.255.0
!
interface Vlan9
ip address 172.16.1.1 255.255.255.0
!
interface Vlan10
ip address 172.16.16.1 255.255.252.0
Page 3 of 4
file://C:\Documents and Settings\Administrator\Desktop\cisco\hycct3... 5/23/2009
!
router rip
network 193.254.18.0
!
ip default-gateway 193.254.18.1
ip classless
ip route 0.0.0.0 0.0.0.0 193.254.18.2
ip route 193.254.1.0 255.255.255.0 193.254.18.2
ip http server
!
!
!
!
control-plane
!
!
line con 0
password 7 0110090A085C535F
login
line vty 0 4
password 7 030C42080F1C701E1E58
login
line vty 5 15
password 7 1311121E585B517A
login
!
!
monitor session 1 source interface Gi1/0/2
monitor session 1 destination interface Gi1/0/3 , Gi1/0/20
!
end
Page 4 of 4
file://C:\Documents and Settings\Administrator\Desktop\cisco\hycct3... 5/23/2009

donggua0713

Building configuration...



Current configuration : 3380 bytes

!

version 12.2

no service pad

service timestamps debug uptime

service timestamps log uptime

service password-encryption

!

hostname HYLCM3750

!

enable secret 5 $1$1Wj1$xm53E3N7vofGk9IL/WuW40

!

no aaa new-model

switch 1 provision ws-c3750g-24ts

vtp mode transparent

ip subnet-zero

ip routing

!

!

!

!

no file verify auto

spanning-tree mode pvst

spanning-tree extend system-id

!

vlan internal allocation policy ascending

!

vlan 2

name vlan2

!

vlan 3

name vlan3

!

vlan 4

name vlan4

!

vlan 5

name vlan5

!

vlan 6

name vlan6

!

vlan 10

name vlan10

!

!

interface GigabitEthernet1/0/1

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/2

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/3

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/4

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/5

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/6

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/7

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/8

switchport access vlan 2

switchport mode access

!

interface GigabitEthernet1/0/9

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/10

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/11

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/12

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/13

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/14

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/15

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/16

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/17

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/18

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/19

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/20

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/21

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/22

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/23

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/24

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/25

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/0/26

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface GigabitEthernet1/0/27

switchport access vlan 6

switchport mode access

!

interface GigabitEthernet1/0/28

switchport access vlan 6

switchport mode access

!

interface Vlan1

no ip address

!

interface Vlan2

no ip address

!

interface Vlan6

ip address 172.16.4.2 255.255.252.0

standby 6 ip 172.16.4.4

standby 6 timers 5 15

standby 6 priority 200

standby 6 preempt

!

ip classless

ip route 172.16.8.0 255.255.252.0 172.16.4.1

ip http server

!

!

!

control-plane

!

!

line con 0

password 7 10420A145640475B

login

line vty 0 4

password 7 0944570A101646405B5D

login

line vty 5 15

password 7 1311121E070F09

login

!

!

end

ssffzz1

2个交换机之间通过那个接口互联的？
PC1 PC2 PC3的缺省网关分别是？？？

donggua0713

原帖由 ssffzz1 于 2009-5-25 17:44 发表
2个交换机之间通过那个接口互联的？


switch 1 的27 28口连到switch 的25 26



PC1 PC2 PC3的缺省网关分别是？？？

PC1 172.16.8.1
PC2 172.16.8.1
PC3 172.16.4.2(172.16.4.1) -----> 疑问所在

donggua0713

对于吧PC3的网关设为172.16.4.2,即可以ping通PC1 PC2,我是这样理解的,PC3发出ping的请求,发现PC1和它不在一个网段,就吧请求转向网关172.16.4.2,网关在自己的路由表里寻找到通向PC1的路由,并使用这个路由联系到PC1,于是能ping通.
但,吧网关设为172.16.4.1,道理和上面的一样啊,为什么不通?

donggua0713

难道是因为switch1没有到172.16.4.0/24的路由,导致ping请求找不到回家的路?

ssffzz1

2个交换机之间通过那个接口互联的？

donggua0713

原帖由 ssffzz1 于 2009-5-25 18:05 发表
2个交换机之间通过那个接口互联的？

switch 1 的27 28口连到switch 的25 26

ssffzz1

帖
SW1:
show int vlan 2
show int vlan 6
show arp
show mac
show ip route

SW2:
show int vlan 6
show arp
show mac
show ip route


语法错误自己修正。