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Webcast-Catalyst9k
New Member

no connection to lan port

Hello all,

I have a 1721 router installed with both an adsl wic and a 4 port switch wic card. My setup is as follows:

pc connected to port 3 (mode access on vlan 20) on the 4 port switch wic  (installed in 1721 router)

port 4 is configured as trunk (encap dot1q) and connected to fasethernet 0 (inbuild of 1721)

fastethernet 0 configured with no ip address

created sub-interface fastethernet 0.20 with encapsulation dot1q on vlan 20

ip address of sub interface 0.20 is 192.168.20.240

pc nic ip address is 192.168.20.245 however cannot ping 20.240 any ideas ?

I want to use only this router with its switch wic for vlans and internet

Thanks

20 REPLIES
New Member

Re: no connection to lan port

The pc is connected to a switch? The port of pc i suppose sent frame untagged so doesn't go on sub if 0.20. What does it mean port 4 is connected on to fast 0? do you have connected a port of switch module on the same router?

Correct me if i'm wrong.. you have configured a port of 4 port module as trunk connected this to fa0 of the same router with sub interface 0.20... and you want that your pc connected to a port in access in vlan 20 of switch module go inside trunk and terminate on subinterface 0.20?

New Member

Re: no connection to lan port

The pc is connected to a switch?   

the pc is connected to a 4 port wic module of router 1721

do you have connected a port of switch module on the same router?

yes I tried to connect from port 4 of the switch on the same 1721 router to the fastethernet 0 port

Correct me if i'm wrong.. you have configured a port of 4 port module as  trunk connected this to fa0 of the same router with sub interface  0.20..

Exactly

and you want that your pc connected to a port in access in vlan 20 of  switch module go inside trunk and terminate on subinterface 0.20?

Exactly

is it possible ?

New Member

Re: no connection to lan port

Ok... for first things... your router doesn't support switched virtual interface (svi)? The cable used are straight or cross?

New Member

no connection to lan port

I am using straight cables

Purple

no connection to lan port

Hi,

Why did you do this? just configure a vlan 20 interface and all hosts in L2 ports belonging to VLAN 20 will use this SVI to route traffic to another VLAN or the internet( via the native routed port of the router).

Regards.

Alain

Don't forget to rate helpful posts.
New Member

Re: no connection to lan port

would you be so kind to write a quick example thanks

also will this work if I need more vlans ?

New Member

Re: no connection to lan port

Cadet.. don't you like cretive user :-)

New Member

Re: no connection to lan port

conf t

interface vlan 20

ip addres 10...... 255.....

no sh

New Member

Re: no connection to lan port

ok so that will be configured on the router and all switch ports just set to access ports on vlan 20

pc gateway will be the vlan 20 ip address correct ?

what ip address will fastethernet 0 have then and do I still need sub-interfaces ?

New Member

Re: no connection to lan port

Yes see if you can configure this svi, with ip address you have configured on sub if... before remove this from it. When the svi is in up up state you must ping the virtual interface  and all will be works correctly and properly configured.

New Member

Re: no connection to lan port

vlan 20 interface did not came up:

Vlan20                     192.168.20.240  YES manual up                    down  

remember also that on interface fastethernet 0.20 I had the command:

ip nat inside

to work back I have configured int fast eth 0.20 with ip, ip nat inside command and encap dot1q

what do you think pls ?

New Member

Re: no connection to lan port

Connect the pc to a port in access for vlan 20.

New Member

Re: no connection to lan port

great Fabio it works, very fast excellent troubleshooting !

can you explain why it did not work with the previous configuration ?

Thanks

New Member

no connection to lan port

Remember for your knowledge, if there is no port up in that vlan or that vlan is not configured on up trunk links the state of that svi is up down. The second down is phisical link, the up is the state of the virtual interface. Have a nyce Christmas.

Purple

no connection to lan port

Hi Fabio,

Yes I like creative users 

great troubleshooting session from you.

Regards.

Alain

Don't forget to rate helpful posts.
New Member

Re: no connection to lan port

You too Alan... it was simple this time i have seen your troubleshooting in other posts, and you are great.

Purple

no connection to lan port

Hi Fabio,

thanks but I'm far away from some other users here which are really experts.

Regards.

Alain

Don't forget to rate helpful posts.
New Member

Re: no connection to lan port

Thanks Again, Happy Christmas !

New Member

no connection to lan port

remember to close the post as resolved, for other user who can be your same problem--- happy xmass again.

New Member

no connection to lan port

what have you done previously was strange... the switch port was on the same router and the mac address was seen on a switched port and on a fa0/0 port... it and also the switch was seen in transit from a trunk port... Maybe the router see that mac address on it's cam table and doesn't respond to the same mac from a fa 0. The configuration was wrong conceptually, and other test will be necessary to give a proper response to your question, but i think what i previously written can be a possible cause.

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