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Webcast-Catalyst9k
New Member

Duplicate VLAN addresses??

Hey everyone,

Need more advice please. If you didn't already know I am a 3rd year Networking and Systems Support student so please don't laugh if I am being a complete nooby no sense! lol.

I am having a some difficulty VLAN addressing on the dual the layer 3 switches. On both DLS switches I beleive the VLAN IP addresses should match each other?? Or am I wrong in saying do?? Reason I ask is because I am being displayed with Duplcate addresses of the VLANs. I have DLS1 & DLS2 configured with the following VLANs:

Capture.JPG

DLS1

interface Vlan1

ip address 172.16.0.1 255.255.255.0

!

interface Vlan100

ip address 172.16.1.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan200

ip address 172.16.2.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan300

ip address 172.16.3.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan400

ip address 172.16.4.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan500

ip address 172.16.5.1 255.255.255.0

ip helper-address 172.16.0.10

DLS2

interface Vlan1

ip address 172.16.0.1 255.255.255.0

!

interface Vlan100

ip address 172.16.1.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan200

ip address 172.16.2.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan300

ip address 172.16.3.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan400

ip address 172.16.4.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan500

ip address 172.16.5.1 255.255.255.0

ip helper-address 172.16.0.10

DLS1 - Full Show Run

hostname DLS1

!

!

!

!

!

ip routing

!

!

!

!

!

!

!

!

!

!

spanning-tree mode rapid-pvst

spanning-tree portfast default

spanning-tree vlan 1,100,200,300,400,500 priority 24576

!

!

!

!

interface FastEthernet0/1

!

interface FastEthernet0/2

!

interface FastEthernet0/3

!

interface FastEthernet0/4

!

interface FastEthernet0/5

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/6

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/7

channel-group 1 mode desirable

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/8

channel-group 1 mode desirable

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/9

!

interface FastEthernet0/10

!

interface FastEthernet0/11

!

interface FastEthernet0/12

!

interface FastEthernet0/13

!

interface FastEthernet0/14

!

interface FastEthernet0/15

!

interface FastEthernet0/16

!

interface FastEthernet0/17

!

interface FastEthernet0/18

!

interface FastEthernet0/19

!

interface FastEthernet0/20

!

interface FastEthernet0/21

!

interface FastEthernet0/22

!

interface FastEthernet0/23

!

interface FastEthernet0/24

!

interface GigabitEthernet0/1

!

interface GigabitEthernet0/2

!

interface Port-channel 1

switchport trunk encapsulation dot1q

switchport mode trunk

spanning-tree portfast disable

!

interface Vlan1

ip address 172.16.0.1 255.255.255.0

!

interface Vlan100

ip address 172.16.1.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan200

ip address 172.16.2.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan300

ip address 172.16.3.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan400

ip address 172.16.4.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan500

ip address 172.16.5.1 255.255.255.0

ip helper-address 172.16.0.10

!

ip classless

!

!

!

!

!

!

!

line con 0

line vty 0 4

login

!

!

!

end

DLS2 - Full Show Run

hostname DLS2

!

!

!

!

!

ip routing

!

!

!

!

!

!

!

!

!

!

spanning-tree mode rapid-pvst

spanning-tree vlan 1,100,200,300,400,500 priority 28672

!

!

!

!

interface FastEthernet0/1

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/2

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/3

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/4

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/5

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/6

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/7

channel-group 1 mode desirable

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/8

channel-group 1 mode desirable

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/9

!

interface FastEthernet0/10

!

interface FastEthernet0/11

!

interface FastEthernet0/12

!

interface FastEthernet0/13

!

interface FastEthernet0/14

!

interface FastEthernet0/15

!

interface FastEthernet0/16

!

interface FastEthernet0/17

!

interface FastEthernet0/18

!

interface FastEthernet0/19

!

interface FastEthernet0/20

!

interface FastEthernet0/21

!

interface FastEthernet0/22

!

interface FastEthernet0/23

!

interface FastEthernet0/24

!

interface GigabitEthernet0/1

!

interface GigabitEthernet0/2

!

interface Port-channel 1

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface Vlan1

ip address 172.16.0.1 255.255.255.0

!

interface Vlan100

ip address 172.16.1.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan200

ip address 172.16.2.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan300

ip address 172.16.3.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan400

ip address 172.16.4.1 255.255.255.0

ip helper-address 172.16.0.10

!

interface Vlan500

ip address 172.16.5.1 255.255.255.0

ip helper-address 172.16.0.10

!

ip classless

!

!

!

!

!

!

!

line con 0

line vty 0 4

login

!

!

!

end

Can you see of I have done this wrong? If someone could check my configs too that would be great.

Thank you!

2 REPLIES
New Member

Re: Duplicate VLAN addresses??

Hi John,

I think you might be getting confused with a function / technology called HSRP.

Basically if you have two layer 3 switches serving clients and want a HA configuration where if one fails the other will take over Layer 3 forwarding operations you need HSRP (which sounds like what your trying to achieve).

So in terms of your configurations each DLS should have a different IP for each Vlan and then under each Vlan interface you configure a HSRP group with the "virtual IP" that clients will use as a default gateway.

I hope this makes some sense if you want to know more about HSRP let me know.

Thanks,

Dunc

Sent from Cisco Technical Support iPhone App

New Member

Duplicate VLAN addresses??

Thanks Duncan,

Yeah I will be using HA in terms of Gateway Load Balancing Protocol I haven't gotten that far as I am doing a top down design and unfortunetly PacketTracer does not support HSRP or GLBP. Configuration will need to happen in the lab but until then I am getting familar with the commands. Presentation is in 6 weeks to show a fully operational campus network with 5 branch offices. Plenty of time. I hope!

Thanks again.

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