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New Member

Switch to Router connection

My internal switches are connected to a Firewall which is connected to an outside 3750G switch.

The outside 3750G switch is connected to a Cisco 3825 Router which has a T3 card for Internet access.

Right now the switch is connected to the router but the type of port is unspecified.

Do I need to make this a trunk port or an access port? Anything else I need to do to this port ?

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Switch to Router connection

These commands are applicable only to the switch. There isn't anything you need to do on the router end. You might want to set the speed/duplex to match on both ends, if auto setting is giving you problems.

HTH

Sundar

5 REPLIES
Hall of Fame Super Bronze

Re: Switch to Router connection

It's recommended to force the mode to access or trunk in order to avoid the autosensing feature.

I also recommend enabling portfast on the port as well as making sure the speed/duplex match at each end.

Re: Switch to Router connection

Hi,

By default, all switchports belong to vlan 1. It should work as it is. But, if you want then you could change it to another vlan. The only criteria is that the port to the outside interface of the firewall and the interface to 3825 has to be on the same vlan as these two interfaces will belong to the same IP subnet. Configure the port as an access port that way the default mode (dynamic desirable) doesn't try to form a trunk association.

int f0/1

description interface to firewall

switchport mode access

switchport access vlan 2 --> Optional setting

spanning-tree portfast

int f0/2

description interface to outside 3825 router

switchport mode access

switchport access vlan 2 --> Optional setting

spanning-tree portfast

Hope this helps!

Sundar

New Member

Re: Switch to Router connection

Thanks for the info, if I set the switch port that connects to the router as

switchport mode access

spanning-tree portfast

Do I do the same of the router port ?

Note: The ports on the switch are all in vlan 1 on the same subnet as the router port.

Re: Switch to Router connection

These commands are applicable only to the switch. There isn't anything you need to do on the router end. You might want to set the speed/duplex to match on both ends, if auto setting is giving you problems.

HTH

Sundar

New Member

Re: Switch to Router connection

Both ports are gigabit so Auto is the only way to go.

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