Converting layer 3 port to layer 2

[sivakumar.ks]

Hi Guys,

I need to convert layer 3 interface to layer 2 in a 3750 switch.

That is I have a packet shapping device which work on layer 2 and all the packet from inside interface of PIX need to be pass via the packet shapping device so that it can log all the traffic passing via pix.

I need to convert two ports i.e for example gi1/0/1 and gi1/0/2 to layer 2 and port gi1/0/31 and gi1/0/32 Layer 3 connected to pix firewall via vlan 49 using switch port access vlan 49. All the traffics passing via port gi1/0/31 and gi1/0/32 should log in the port gi1/0/1 and gi1/0/2 were pack shaping device are connected which works on layer 2. Can one help me to achieve that pls.

Thanks.

siva

[spremkumar]

Hi

I feel you want to convert routed(L3)interface to a normal L2 interface then in that case you need to key in switchport command under the interface mode to force the same to act as an L2 interface.

Once the same is done you can configure the port either as a trunk or access port based on the requirement.

I feel in your case you want to make that as an access port which you can do it using switchport mode access..

regds

[mihanlin]

Hi Siva,

To convert a layer 3 port to a layer 2 on a switch, you need to issue the command:

"switchport"

to convert a layer 2 to layer 3, try:

"no switchport"

Hope this helps,

Michael

[sivakumar.ks]

Hi Michael,

I need something like monitor or span port , so that I can monitor traffic coming in and out via source gi 1/0/31 and gi 1/0/32 in the port gi1/0/1 were the packet shapping device is connected.

In 3500 series I use to span and mirror the port for capture packet via ethreal for a specific port. I need to same capability so that I can capture all incoming and outgoing pack via gi1/0/31 and gi1/0/32 in port gi1/0/1 and gi1/0/2 in packet shaping device Exinda.

[jolmo]

You can use SPAN as in 3500 series:

monitor session 1 source interface gig1/0/31

monitor session 1 source interface gig1/0/32

monitor session 1 destination interface giga1/0/1

monitor session 1 destination interface giga1/0/2

Hope this helps

[sivakumar.ks]

Hi,

I tried the yesterday and became show stopper for the whole network. I have attached the configuration of the switch where I did. Please have a look. It is a 3750 stake farm.

siva

[jolmo]

I have seen your config but I can not identify source ports gig1/0/31 and gig1/0/32. Where are they?

[minumathur]

Hi.

You need to first login into interface through config t , then interface etc..

1) To convert layer 3 to layer 2

" no switchport "

2) To convert layer2 to layer 3

" switchport "

This will solve your problem.... please rate this post.

-Minu

[Ciro Gustavo Mele]

Switch(config)#interface FastEthernet 0/1
Switch(config-if)#no switchport
Switch(config-if)#ip address 200.1.1.1 255.255.255.0
Switch(config-if)#no shutdown

The no switchport command makes the interface Layer 3 capable.

[Vishnu Vardhan S]

Go inside interface configuration mode and use the command "switchport"