Help me define a VLAN on Cisco Switches.

Posted on 2006-04-10
Last Modified: 2012-05-07
I know this might be easy for most experts, but I needed this setup ASAP, and I was hoping I get help doing it.
I have a network with a Catalyst 4507 with 48Gbps Ethernet ports, and 16-1Gbps SX  ports.
Also I have as distribution switches multiple 2950's .

I have a server (proxy1, IP connected to port Gi 7/5 (which is Gig over UTP).
I currently have only one vlan for the whole network.
The subnet is

my 4507's IP is

I have Pc (I call it Gif, IP which is connected to port (4) in switch
the switch "" is connected through its port Gi01 to port Gi4/3 in the 4507

and another PC ( I  call it Dave, IP which is connected through its port Gi01 to port (9) in switch
the switch "" is connected to port Gi4/5 in the 4507

[Gif]--------port4-[++++++]=Gi01===Gi4/3=[ 4507             ]=Gi4/5=====Gi01=[+++++++]--port9-----[Dave]                        [     ]                        
                                                                 [                      ]-Gi7/5------[Proxy1]

1) PC "Gif" will be able to only see the server "proxy1"
2) PC "Dave" will be able to only  see the server "proxy1"
3) "Proxy1" will be available to any one else in the network.
Note: don't care if "Gif" can see "Dave" or not.

How can I establish this

Thanks in advance.
Question by:hkunnana
    LVL 9

    Expert Comment

    hi, there

    ok so as I see it you will need 3-4 VLAN's

    Lets name them:
    VLAN 1 Management VLAN
    Proxy 1=VLAN 2
    David = VLAN 3
    GIF = VLAN 4

    Cisco 4507
    Now on the cisco 4507 you assign each VLAN an IP Address ex.
    VLAN 1
    VLAN 2
    VLAN 3
    VLAN 4

    VLAN Trunking:
    interface FastEthernet0/4
    switchport trunk encapsulation dot1q
     switchport trunk allowed vlan 2,3,4
     switchport mode trunk

    So on these switches where these users are connected you first of all enable VLAN trunking.
    then you can do it per port basis. Lets take the "GIF" machine
    on the port where it is connected you now do :

    interface FastEthernet0/4
    switchport trunk encapsulation dot1q
     switchport trunk allowed vlan 2
     switchport mode trunk

    switch that the port is allowed to run vlans through (even if you set just
    VLAN 2, cisco will automatically add VLAN 1 and VLAN 1002-1005) to the port
    and set the port to trunk mode aswell. Trunk mode tells the switch that
    a number of VLANS can go through it.
    Last line is usually the mother of all screw-ups. If you forget that, you
    won't get your VLAN working. Simple as that.
    conf t
    interface FastEthernet0/1
     duplex half
     speed 10
     switchport access vlan 2

    You could also make a VTP domain so you will basically setup all on one switch per MAC address it could later turn out to be a mess but is a nice feature.

    LVL 12

    Author Comment

    Thanks Cooledit, but I see that using these subnetting (specially with these addresses) will miss my network up.
    I have read a little and manged to do the following till now:

    I have created VLAN number 10, and createda a VTP domain DOM1. at first I tried to make the 4507 s server for the domain and then made all other switches as clients, and set the corrsponding ports  for the PC's in VLAN-10 only, and the port for Proxy1 in VLAN 1,10 . but that didn't work good, as the PC's were not isolated as I wished.
    Then I've made all switches as VTP servers, and using VLAN 10 , assigned ports corrsponding to the PC's to static VLAN10, all other ports only VLAN1, and the trunk port to VLANs 1&10.

    that did work to isolate the network of the PC's with the proxy1 from my network. Now what is missing is the need to allow all other netwok members to also reach the Proxy1.

    LVL 9

    Accepted Solution

    hi, there

    this is the problem VLAN 1 is the default management VLAN and is assigned to all ports.
    you should rather create just 1 more VLAN

    as you want to have 3 different "subnet" broadcasting doamin, so PC dave can talk to the proxy 1 that is 2 VLAN.

    VLAN 1 Proxy1 needs access to PC Dave ---- PC-GIF

    VLAN 1 is the default Management VLAN do not use this one.
    VLAN 2 Proxy1 Access to VLAN 1, VLAN 3,
    VLAN 3 PC Dave Access to VLAN 2,  
    VLAN 4 PC GIF Access to VLAN 2

    This is the best way I can explain it.

    LVL 12

    Author Comment

    hi, Cool,

    It seems reasonable, I will try it and let you know.



    Featured Post

    IT, Stop Being Called Into Every Meeting

    Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

    Join & Write a Comment

    Quality of Service (QoS) options are nearly endless when it comes to networks today. This article is merely one example of how it can be handled in a hub-n-spoke design using a 3-tier configuration.
    PRTG Network Monitor lets you monitor your bandwidth usage, so you know who is using up your bandwidth, and what they're using it for.
    After creating this article (, I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
    In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor ( If you're interested in additional methods for monitoring bandwidt…

    746 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    18 Experts available now in Live!

    Get 1:1 Help Now