04-02-2009 04:21 AM - edited 03-06-2019 04:57 AM
Hi
I have a router doing some routing this is connected to an access switch port, I would like to add a subinterface to it can someone help me with setting it up as I've never done this before.
Here are the details
Router:
interface FastEthernet0/0
ip address 10.32.1.3 255.255.255.0
duplex auto
speed auto
standby 32 ip 10.32.1.1
standby 32 priority 110
standby 32 preempt
standby 32 track FastEthernet0/1 30
exit
Switch
interface GigabitEthernet2/0/48
switchport mode access
spanning-tree portfast.
I want to create a fa0/0.0 interface, is that possible on a 2800 router? When I initially created it I lost connection to the router, here's what I added:
int fa 0/0.0
ip address 10.32.50.0 255.255.255.0
exit
Could I have lost connection to the router becuase the switch is set as access mode instead of trunk?
After a short while I tried the same thing above but this time just did the below:
int fa 0/0.0
Description Test interface
exit
But when I run "show run" I can't see this interface anywhere it only shows me fa0/0 and fa0/1. Any thoughts?
Also I then thought let me add the address "10.32.50.0 255.255.255.0" again but this time the router says "Bad mask /24 for address 10.32.50.0". Any thoughts on this?
Thanks in advance
Dan
Solved! Go to Solution.
04-02-2009 04:29 AM
Dan
Have a look at this doc -
http://www.tech-recipes.com/rx/1853/Cisco_switch_802_1q_trunk_to_router_on_a_stick/
Jon
04-02-2009 04:29 AM
Hello Dan,
use the following examples adapt to your scenario
router side:
use two subinterfaces with different vlan-id and remove ip address from main interface
int f0/0
no ip address
int f0/0.10
enc dot1q 10
ip address 10.32.50.1 255.255.255.0
int f0/0.20
enc dot1q 20
ip address 10.32.60.1 255.255.255.0
switch side:
int f0/15
switchport
swithcport trunk enc dot1q
swithcport mode trunk
switchport trunk allowed vlan 10,20
>> he address "10.32.50.0 255.255.255.0" again but this time the router says "Bad mask /24 for address 10.32.50.0". Any thoughts on this?
this is the subnet address and cannot be used for any host including a router interface (all 0 in host portion)
Hope to help
Giuseppe
04-02-2009 04:29 AM
Dan
Have a look at this doc -
http://www.tech-recipes.com/rx/1853/Cisco_switch_802_1q_trunk_to_router_on_a_stick/
Jon
04-02-2009 04:45 AM
Then have a look at this one.
04-02-2009 05:07 AM
Hi,
Thank you all for this. Can someone suggest how I can do this remotely? I.e the exact process to take without losing connection?
Thanks
Dan
04-02-2009 05:27 AM
Dan
You need to access the router through another interface ie. not fa0/0
If you can do thiss log onto the switch and change the port to a trunk port first. Be aware that as soon as you do this you will lose connectivity between the switch and the router. Then configure fa0/0 interface as described and it should start communicating again.
Jon
04-02-2009 05:36 AM
Ahh, so that's a problem as I onlyt have one link to this site and it's this link that's going to be dropped. I'll find a way round somehow. Appreciate the info though.
Thanks
Dan
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