VLAN ? : Making a port a member of more than one VLAN

dissolved

I think you can with the multiport command right?
Let's say you have 3 VLANs on your switch.
VLAN1 (default) 192.168.1.0
VLAN2 192.168.2.0
VLAN3 192.168.3.0

If I assign port number 5 to be part of VLAN2 and VLAN3, can I choose what IP address to assign the computer plugged into port number 5? I'm assuming I can assign it an IP of either VLAN2 or VLAN3 addressing scheme?

Thanks

viper75

You can only have one port on one vlan. You can NOT have port 5 be on both vlan 2 and 3. The switch will not allow you too. If you have port 5 on vlan 2 you must assign the PC the correct IP address that cooresponds to vlan 2 or your PC will not communicate on the network.

Your router (gateway) will let your computer communicate with other vlans if the router is configured properly.

dissolved

Thanks man. Long time no talk. How ya been? Did I give you my new AIM?

Anyway thanks for responding. I think I read in my sybex book you can make a server a member of 2 vlans at the same time. So clients in other VLANs dont have to cross a router to get to the fileserver. I must of read it wrong though (too much late studying)

The reason I posted this question. Was because we run 2980G switches at work. We have 2 vlans 172.25.22.0 and 172.42.22.0
My boss said any port on the switch can be in either VLAN. It just depends on what IP address the client has. I told him that was not possible. He said thats what he was told (he's not a cisco guy). I tried it and it does indeed route either address. We are using 2980G switches with a catalyst 4000 core switch.

viper75

I'm pretty sure you need to have 2 NICs on the server for that to be able to work, one on each vlan.

Your boss might be thinking of trunked ports...in reality they do belong to multiple vlans because they carry vlan info. across your switches, but on regular fastethernet ports configured like this "switchport access vlan X" it will only be part of vlan X and none else. If you have access to a switch go to any fastethernet port and type"

"switchport access vlan 5"

hit [enter] the try to put the same port on vlan 6

"switchport access vlan 6"

Do a copy run start...then do a show run and see what vlan that port belongs too.

I just did it on one of my switches and it does not let you assign 1 port to multiple vlans.

dissolved

I see what you're saying. 2 nics, one in each VLAN.

Here is a sh run from my switch Let me know what you think. Not sure if I'm understanding this concept correctly. Note port 2 and 3

spanning-tree vlan 1 hello-time 10
spanning-tree vlan 3 hello-time 10
ip subnet-zero
!
!
!
interface FastEthernet0/1
port security max-mac-count 1
!
interface FastEthernet0/2
switchport multi vlan 1,3
!
interface FastEthernet0/3
switchport access vlan 3
switchport multi vlan 1,3
!
interface FastEthernet0/4
switchport access vlan 2
!

Cut off the rest

viper75

Ok I see what you mean now. I will try this configuration at work tomorrow, we have 10 vlans at work.

garv221

We have 80 Vlans at work...

viper75

garv221 wrote:

We have 80 Vlans at work...

Dam!!!

dissolved

Im in the switch now. Will post the sh run

keenon

50 here in this location

garv221

viper75 wrote:

garv221 wrote:

We have 80 Vlans at work...

Dam!!!

Ya! The admin VLAN is where I spend most of my time, but the other VLANs are for our tenants (3500), so we have them on VLANS and switch port protected.

dissolved

ok, the sh run command doesnt work. I think this is the catOS and not IOS. Great, I know nothing about cat. How do you display the startup config etc?
Thanks

keenon

um , show run does work on cat OS just did it on 6500 .. and sh ver
the show run shows the non default config
but you also can use show config all which shows both the default and non default

dissolved

Here I am logged into a 2980g switch here. I cant even get into global config mode. ???? Any ideas?


Cisco Systems, Inc. Console




Enter password:
dhsscat2980_21 en

Enter password:
dhsscat2980_21 (enable) config t
This function provided by set commands. Use 'set help' for more info.
dhsscat2980_21 (enable)

keenon

yep that is a cat OS.. once you login your automatically in enable and config mode notice "(enable)" i'm opening msn you can im if anymore questions.

in cat Os you have to use "set " commands when configuring ports

dissolved

thanks man. Got this post kind of late. WIsh I could of caught you on MSN.
THanks!
will you be on later

keenon

sure i'll get on now and stay on till 4 or 4:30 cst

schneeman

viper75 wrote:

I'm pretty sure you need to have 2 NICs on the server for that to be able to work, one on each vlan.

Your boss might be thinking of trunked ports...in reality they do belong to multiple vlans because they carry vlan info. across your switches, but on regular fastethernet ports configured like this "switchport access vlan X" it will only be part of vlan X and none else. If you have access to a switch go to any fastethernet port and type"

"switchport access vlan 5"

hit [enter] the try to put the same port on vlan 6

"switchport access vlan 6"

Do a copy run start...then do a show run and see what vlan that port belongs too.

I just did it on one of my switches and it does not let you assign 1 port to multiple vlans.

Viper;
Trunking is different situation in here.Trunking using between two switches.It takes one port and it connects different virtual lans on SEPERATE switchs.But this problem is on the same switch i think.Same switch has got VLAN2 and VLAN3 and fastethernet siwtch port wants to member of VLAN2 and VLAN3 same time.This is strange and i think it is possible on later models of cisco.Because vice versa is possible on every switch.But this is the against the nature of Virtual Lan principle.Because we can use vlans to prevent boardcast storming and provide network security to seperate broadcast domains.If this guy means to that using same VLAN name on separate switch this is completely wrong because vtp domain cannot accept it on every model of Cisco.