InterVLAN routing help

Wick3ed

n00b
Joined
Aug 13, 2013
Messages
19
Good Morning,
I'm having an issue with getting my Vlans to talk to each other. I have the SG 300-28P switch set to layer 3 have 3 VLANs on the switch (1) default vlan 192.168.1.0 (2) BoilerHouse 192.168.0.1 (3) Data 192.168.50.1 The Data vlan is the gateway to the internet and has the DNS server the other 2 netowrks are just for plc devices ip camera's and meter reading. I need to be able to ping between the 3 networks and have internet connection to them too. I'm really new to switches and will try my best to get the info you need to help. I did call Cisco for tech support but I needed a contract number from my reseller not sure how long that will take but I'm in a pinch.

Also have the latest firmware for the switch 1.3.0.62
Thank you for your help.
 

Shadowspawn

[H]ard|Gawd
Joined
Sep 17, 2002
Messages
1,870
So, you have created the VLAN's?

#vlan 2
#name BoilerHouse
...etc

Have you created the VLAN interfaces?

#int vlan 1
#ip address 192.168.1.1 255.255.255.0
...etc

If you want the VLANs to communicate you have to either use a router or make your switch a layer 3 switch by turning on IP routing...

It just occurred to me that you are using the web interface to configure it. I haven't used these switches personally, but I believe you need to set the system mode to router.
 

firedrow

Limp Gawd
Joined
Oct 11, 2013
Messages
161
I don't know the Cisco switches specifically, but Shadowspawn is right, you need something to route between the VLANs. Physically they share 1 piece of hardware, logically they are 3 seperate networks. So you need a router with a VLAN trunk/Tagged port setup to route between VLANs or if the switch can do the Layer 3 routing itself, it needs to be told how to do that.

Google "router on a stick" and "one-armed router" and you should be able to find what you need.
 

thrash408

Limp Gawd
Joined
Jan 22, 2010
Messages
367
Shadow is right, enable IP Routing and then ensure your vlans are set up as he stated. You will also need to set the ports to the specific vlan unless you are trunking the traffic.
 

Wick3ed

n00b
Joined
Aug 13, 2013
Messages
19
Not using the web interface as I read it may cause so issues. I do have the switch set to layer 3 from the default layer 2. Interfaces all set up, Vlans all named and networks are talking but not talking to the other subnets. That's were I'm lost at is to set the ports to the specific vlan. If I tag port 5 to vlan 2 how will vlan 2 talk to the other networks?

Thank you for your time
 

djflow195

Weaksauce
Joined
Sep 6, 2011
Messages
102
You're overthinking this.

create the vlans:

Code:
vlan XXX
  name XXX_Name

create the layer 3 vlan interfaces:

Code:
int vlan XXX
  ip address 1.2.3.4 255.255.255.0
  no shut

set the vlan on an access interface (all frames are on vlan XXX):

Code:
int fa0/0
  switchport mode access
  switchport acces vlan XXX

set the native vlan on a trunk interface (what vlan if the frame is untagged):

Code:
int fa0/1
  switchport mode trunk
  switchport trunk native vlan XXX

set trunk encapsulation (may not need this, assume config from above to set trunk):

Code:
int fa0/1
  switchport trunk encapsulation dot1q

set allowed vlans on trunk (assume config from above to set trunk):

Code:
int fa0/1
  switchport trunk allowed vlan XXX (use ? to see different values)

set layer 3 routing on switch, without this your layer 3 interfaces will not route:

Code:
ip routing

Assume:
Code:
vlan 2
  name VLAN2
vlan 3
  name VLAN3

int vlan 2
  ip address 10.0.0.1 255.255.255.0
  no shut

int vlan 3
  ip address 10.0.1.1 255.255.255.0
  no shut

int fa0/0
  switchport mode access
  switchport access vlan 2
  no shut

int fa0/1
  switchport mode access
  switchport access vlan 3
  no shut

ip routing

Frame comes in fa0/0 source ip 10.0.0.2 destination ip 10.0.1.2.
Frame goes to int vlan 2.
Connected routes in the routing table show int vlan 2 handles 10.0.1.0 / 24 (verify with "show ip route conn").
Frame goes to int vlan 3.
Frame goes out fa0/1 whose connected device is 10.0.1.2.

This is simplified as there is much more happening in the switch with ARP, ARP tables, MAC, MAC tables, etc.

To answer your question port 5 on vlan 2 will talk to the layer 3 vlan 2 interface. From there it will route to the appropriate layer 3 interface (ie. layer 3 vlan 3 interface same switch, layer 3 vlan 3 interface on another connected switch, router connected to an access port vlan 2, router connected to a trunk port that handles vlan 3, etc.) and go from there. Just make sure your target vlan has a layer 3 interface and you are good to go.

Suggest you read up on "How To Configure InterVLAN Routing on Layer 3 Switches":

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_configuration_example09186a008019e74e.shtml
 
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