Hello People,

So starting from beginning, I have router based on CentOS system with DHCP server. In one eth I have fiber converter attached in second one I have Cisco Catalyst switch connected. From the switch rest of ports are used to provide internet traffic to rest of network. I wanted to divide each segment of network (based on switch ports) that they don't see each other (it'll be good for me if someone will connect his wireless router to the network not to WAN by LAN port and start be a second DHCP server).

So my network configuration:
CentOS:
DHCP with range 10.0.0.1/8 network

Switch ports:
1 - CentOS DHCP
2 - second server
3 - first part of network
4 - second part of network
5 - third part of network
6 - link to office building
7 - next part of network

Parts of networks I've assigned IPs 10.network_part.subnet_part.client_ip so I have addresses for clients: 10.1.1.2/8, 10.2.1.3/8, 10.3.0.4/8, etc ...

I've decided to give each port it's own VLAN like below:
Port / VLAN
1 / trunk
2 / 102
3 / 103
4 / 104
5 / 105
6 / 106
7 / 107

I've configured switch ports by using:
(config)# interface Gi0/Port_Number
(config-if)# switchport access vlan VLAN_NUMBER

and configured trunk port for router:
(config)# interface Gi0/1
(config-if)# switchport trunk allowed 1-107
(config-if)# switchport trunk encapsulation dot1q
(config-if)# switchport mode trunk

And after doing that whole network stopped working.
I think that cisco part of configuration is OK (at least customer ports, I don't know if there is any additional info needed for trunk port).
On CentOS router I didn't setup anything regarding VLANs ...

Could any help me with proper configuration?

Network diagram pasted in jpg.

Best Regards

Attached Thumbnails

 

you are routing /8 subnets??? that's just mental... I hope it makes sense in a wider context, but it doesn't sound like it does.

as you mentioned you haven't set up *anything* for vlans on the centos side, that's a pretty good reason it's not working. To set up vlan interfaces, this looks reasonable. http://wiki.xdroop.com/space/RedHat/VLAN+definition it's all pretty easy actually.

You might want to make one network native to the centos router. only having vlan interfaces can lead to lots of problems. "switchport trunk native vlan 101" for example.

It's not I'm routing whole 10.0.0.1/8.
Just when the network started to live I had to have clear view on each line, so each line had it's own 10.x subclass, then on the line each building had it's own 10.x.y subclass. So when it was starting it was clear to know, that this IP 10.x.y.z was line X, building Y on this line, customer Z in that building.

OK but you netmasks are /8 still. They are all the same subnet. Nothing will try to route if its not in a different subnet.

OK, Chris is absolutely right, you have two problems.

You have split your network into 6 vlans, so you need 6 subnets on your router. The /8 you specified are all the same subnet. /8 = 255.0.0.0 ; 10.1.0.0 255.0.0.0 = network 10.0.0.0. 10.2.0.0 255.0.0.0 = network 10.0.0.0. See? doesn't work.

You need something like -

Int Vlan Network Router Addr
eth1 102 10.2.0.0/16 10.2.1.1
eth1:103 103 10.3.0.0/16 10.3.1.1
eth1:104 104 10.4.0.0/16 10.4.1.1
eth1:105 105 10.5.0.0/16 10.5.1.1
eth1:106 106 10.6.0.0/16 10.6.1.1
eth1:107 107 10.7.0.0/16 10.7.1.1

See how the numbers line up? Always helps avoid mistakes if you can do it this way.

Configure the eth interfaces following a guide such as this -

http://www.tummy.com/journals/entrie...0061130_063931

Then configure your trunk on the cisco as you have except add

(config)# interface Gi0/1
(config)# switchport trunk native vlan 102

You will need to configure DHCP pools on your DHCP server with the correct masks (/16) and the correct default gateways, as per the table above.

I would never recommend making a change like this on a live network. Its always bound to bad.

No reason why you couldn't test his with a few spare ports and a couple of laptops.

If in doubt, bench test it first.