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871 connected to a 3550 Catalyst

obmis
Level 1
Level 1

I am looking to create 2 VLAN's. VLAN 1 will be tunneling through a VPN to our corporate office. VLAN10 will be used for contractors to access the internet. I need help configuring the VLAN trunking, DHCP to supply to both VLAN's. I supplied my running configs minus some information. Thanks for your help.

1 Accepted Solution

Accepted Solutions

on the router, enter this command:

sh int f0 switchport

You will see something like this

Administrative Trunking Encapsulation: dot1q

It won't show in the config because there is only one encapsulation option. If you had ISL as another option, it would be shown in the config.

View solution in original post

3 Replies 3

Edison Ortiz
Hall of Fame
Hall of Fame

On the 3550 switchport connected to the router:

interface FastEthernetx/x

switchport trunk encap dot1q

switchport mode trunk

On the router port connected to the 3550:

interface FastEthernetx

switchport

switchport trunk encap dot1q

switchport mode trunk

On the router DHCP pool

ip dhcp excluded-address 10.10.24.254

ip dhcp pool sdm-pool2

network 10.10.24.0 255.255.255.0

domain-name [domain name for contractors]

default-router 10.10.24.254

dns-server [dns server for contractors]

netbios-name-server [ditto]

NAT for that segment

interface Vlan10

ip address 10.10.24.254 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

ip nat inside

ip virtual-reassembly

ip route-cache flow

access-list 130 permit ip 10.10.24.0 0.0.0.255 any

All entries went in with out a problem. Except the command on the router port connected to the 3550. In this case I am using interface fastethernet0. Switchport mode trunk works but am unable to do the switchport trunk encap dot1q. I can put it in but it does not seem to go into the running config. I saved the config and rebooted. Do I need a different IOS to support VLAN trunking? My reseller said no. Let me know. Thanks.

Current IOS c870-advsecurityk9-mz.124-11.XJ4.bin

on the router, enter this command:

sh int f0 switchport

You will see something like this

Administrative Trunking Encapsulation: dot1q

It won't show in the config because there is only one encapsulation option. If you had ISL as another option, it would be shown in the config.

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