Introduction

The goal of this document is describe how to configure VLANs over a Red Hat 5 distribution and also over a Cisco Catalyst 2950-24.

Scheme

VLAN configuration

VLAN creation on a Red Hat 5 distribution

Starting point: we have a server with a network adapter installed and we want to create 2 VLANs (e.g. VLAN5 and VLAN6).

In this situation, first of all we need to configure our network adapter. To do this, we need to modify (or create in case it doesn’t exist) with a text editor (e.g. vi editor) the following archive:

/etc/sysconfig/network-scripts/ifcfg-eth0

The content of the file should have the following lines:

DEVICE=eth0

BOOTPROTO=static

BROADCAST=192.xxx.xxx.255

IPADDR=192.xxx.xxx.xxx

HWADDR=xx:xx:xx:xx:xx:xx

NETMASK=255.255.255.0

NETWORK=192.xxx.xxx.0

ONBOOT=yes

TYPE=Ethernet

We the fields: IPADDR, HWADDR, NETMASK and NETWORK, will depend on the network scheme that you have.

Now we can create our VLANs. As well as we have done to configure the network adaptor, we create two file (one per VLAN):

/etc/sysconfig/network-scripts/ifcfg-vlan5

/etc/sysconfig/network-scripts/ifcfg-vlan6

The files should contains:

(VLAN 5)

VLAN=yes

VLAN_NAME_TYPE=VLAN_PLUS_VID_NO_PAD

DEVICE=vlan5

PHYSDEV=eth0

BOOTPROTO=static

ONBOOT=yes

TYPE=Ethernet

IPADDR=212.xxx.xxx.101

NETMASK=255.255.255.240

(VLAN 6)

VLAN=yes

VLAN_NAME_TYPE=VLAN_PLUS_VID_NO_PAD

DEVICE=vlan6

PHYSDEV=eth0

BOOTPROTO=static

ONBOOT=yes

TYPE=Ethernet

IPADDR=192.xxx.xxx.11

NETMASK=255.255.255.0

Also we need to add a gateway in the configuration file:

/etc/sysconfig/network-scripts/route-vlan5

like:

0.0.0.0/0 via 212.xxx.xxx.98

After that, we need to modify with a text editor the following configuration file:

/etc/resolv.conf

This file contains information that determines the operational parameters of the DNS resolver. We should add the following lines:

nameserver 212.xxx.xxx.98

search fix.access.vtx.ch

With these steps, we have configured our VLANs.

Switch configuration

First connection to a Cisco switch should be done through it console port with the Cisco console cable. The Catalyst 2950-24 has the console port at the rear.

Notice that our PC must have a serial port, but if it hasn’t one we should use a serial port-to-usb adapter.

Configuring the console connection

In order to connect we should configure a HyperTerminal connection as shows in the figure:

This configuration is needed to be applied in the COM port where we have connected the Cisco console cable (or the serial port-to-usb adapter). If we have problems to establish which port we are using, follow these steps:

Start à Control Panel

Control Panel à System

System à Hardware

Hardware à Device Manager à Ports (COM & LPT)

In the above figure, we can see that we are using the serial port-to-usb adapter in the COM3.

So now, we have determined our serial port and we can configure the HyperTerminal connection.

Console connection

Once we have configured the HyperTerminal, we start the connection:

And after that, we turn on the switch. At this point we see the Catalyst load process:

Switch con0 is now available

Press RETURN to get started.

C2950 Boot Loader (C2950-HBOOT-M) Version 12.1(11r)EA1, RELEASE SOFTWARE (fc1)

Compiled Mon 22-Jul-02 17:18 by xxxxxxx

WS-C2950-24 starting...

Base ethernet MAC Address: xx:xx:xx:xx:xx:xx

Xmodem file system is available.

Initializing Flash...

flashfs[0]: 90 files, 3 directories

flashfs[0]: 0 orphaned files, 0 orphaned directories

flashfs[0]: Total bytes: 7741440

flashfs[0]: Bytes used: 6475264

flashfs[0]: Bytes available: 1266176

flashfs[0]: flashfs fsck took 10 seconds.

...done initializing flash.

Boot Sector Filesystem (bs:) installed, fsid: 3

Parameter Block Filesystem (pb:) installed, fsid: 4

Loading "flash:/c2950-i6q4l2-mz.121-20.EA2.bin"...##############################

################################################################################

###

File "flash:/c2950-i6q4l2-mz.121-20.EA2.bin" uncompressed and installed, entry p

oint: 0x80010000

executing...

Restricted Rights Legend

Use, duplication, or disclosure by the Government is

subject to restrictions as set forth in subparagraph

Rights clause at FAR sec. 52.227-19 and subparagraph

Software clause at DFARS sec. 252.227-7013.

cisco Systems, Inc.

170 West Tasman Drive

San Jose, California 95134-1706

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(20)EA2, RELEASE SOFTWARE

(fc1)

Compiled Wed 19-May-04 03:07 by xxxxxxx

Image text-base: 0x80010000, data-base: 0x80550000

Initializing flashfs...

flashfs[1]: 90 files, 3 directories

flashfs[1]: 0 orphaned files, 0 orphaned directories

flashfs[1]: Total bytes: 7741440

flashfs[1]: Bytes used: 6475264

flashfs[1]: Bytes available: 1266176

flashfs[1]: flashfs fsck took 10 seconds.

flashfs[1]: Initialization complete.

Done initializing flashfs.

POST: System Board Test : Passed

POST: Ethernet Controller Test : Passed

ASIC Initialization Passed

POST: FRONT-END LOOPBACK TEST : Passed

cisco WS-C2950-24 (RC32300) processor (revision H0) with 20913K bytes of memory.

Processor board ID FOC0713W14R

Last reset from system-reset

Running Standard Image

24 FastEthernet/IEEE 802.3 interface(s)

32K bytes of flash-simulated non-volatile configuration memory.

Base ethernet MAC Address: xx:xx:xx:xx:xx:xx

Motherboard assembly number: xx-xxxx-xx

Power supply part number: xx-xxxx-xx

Motherboard serial number: xxxxxxxxxxx

Power supply serial number: xxxxxxxxxxx

Model revision number: H0

Motherboard revision number: A0

Model number: WS-C2950-24

System serial number: xxxxxxxxxxx

Press RETURN to get started!

Clean up the switch

Ok, the switch has finished the load and now it’s waiting us for a new configuration. If it’s a new device, it should ask us for basic parameters configuration, but if not (or if it doesn’t ask us for basic parameters configuration) that means that we need to clean up the previous configuration that it has.

We proceed typing the following commands:

dir flash:

This command show all the folders and files that have been loaded in the switch’s flash memory.

It should be a config.text file. It contains an old configuration. We can delete it but it’s safer if we rename it:

rename flash:config.text flash:config.backup

Now, we reset the switch:

reload

When the switch is rebooting, we can see the entire load’s dialog again, and when it finish, we will be asked if we want to do an initial configuration. We answer yes.

Configure the switch

The following link is a guide to configure our switch:

http://www.cisco.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_22ea/SCG/2950SCG.pdf

The commands that we need in this case are showed below:

Switch# vlan database

Switch(vlan)# vlan 5 name Vlan5

Switch(vlan)# vlan 6 name Vlan6

Switch(vlan)# exit

Switch# configure terminal

Switch(config)# interface range f0/1 - 3

Switch(config-if)# switchport access vlan 2

Switch(config-if)# no shutdown

Switch(config-if)# exit

Switch(config)# interface range f0/9 - 15

Switch(config-if)# switchport mode trunk

Switch(config-if)# switchport trunk allowed vlan 1, 5, 6

Switch(config-if)# no shutdown

Switch(config-if)# exit

Switch(config)# interface f0/16

Switch(config-if)# switchport mode trunk

Switch(config-if)# no shutdown

Switch(config-if)# exit

Switch(config)# interface f0/24

Switch(config-if)# switchport access vlan 6

Switch(config-if)# no shutdown

Switch(config-if)# exit

Switch(config)# interface Vlan5

Switch(config-if)# ip address 212.xxx.xxx.100 255.255.255.240

Switch(config-if)# exit

Switch(config)# ip default-gateway 212.xxx.xxx.98

At the end we will have the following configuration:

version 12.1

no service pad

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

hostname Switch

no logging console

enable secret 5 $1$fTmk$wDTR4Z4XYsoqtN2k/U/3Z.

enable password xxxxxxxxx

ip subnet-zero

spanning-tree mode pvst

no spanning-tree optimize bpdu transmission

spanning-tree extend system-id

interface FastEthernet0/1

switchport access vlan 5

interface FastEthernet0/2

switchport access vlan 5

interface FastEthernet0/3

switchport access vlan 5

interface FastEthernet0/4

interface FastEthernet0/5

interface FastEthernet0/6

interface FastEthernet0/7

interface FastEthernet0/8

interface FastEthernet0/9