topic Re: InterVlan noob problem help in Switching

InterVlan noob problem help

WIZARD1325 — Fri, 08 Mar 2019 21:51:57 GMT

PC1-192.168.10.2

PC2- 192.168.10.3

under Vlan 10

PC3-192.168.20.3

PC4. 192.168.20.4

under Vlan 20

Router default gateway

192.168.10.1. for vlan 10

192.168.20.1 for vlan 20

I can ping 1 and 2 and 2 and 4 in the same Vlan but I cant ping across from vlan 1 to vlan 2 see attachments how i have it set up

I did input the default gateway info under ipconfig on each pc

What am i doing wrong?

thanks in advance

Re: InterVlan noob problem help

Deepak Kumar — Thu, 15 Feb 2018 09:36:40 GMT

Hi,

I can see that you have connected L2 switch to system and L2 switches are connected to router. So your system default gateway must be your router interface IP.

If you configured already default gateway as router interface IP then please share router routing or check for any ACL configuration.

Why we need router interface IP as default gateway on your system?

Because your switch is L2 and could not perform inter vlan routing.

Regards,

Deepak Kumar

Re: InterVlan noob problem help

Mark Malone — Thu, 15 Feb 2018 09:38:14 GMT

Hi
what way is this setup is it router on a stick design , with sub interfaces on the router or an actual trunk with vlan interfaces on the router , can you provide the config to see whats been setup , is ip routing enabled on the router it should be by default to allow intervlan communication

rns design guide
http://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/336-cisco-router-8021q-router-stick.html

Re: InterVlan noob problem help

WIZARD1325 — Thu, 15 Feb 2018 09:50:57 GMT

whow whoowww whooowwwww fancy talking.....im just a noob here.

im just reading and following what the book tells me to do.

it said L2 switches cant do it so therefore i use a router to do it.

i inputed the numbers above made the vlans and such

but still cant ping from 1 vlan to another

I dont know what a stick design means or is I am just on chapter 2 here.

or sub interface what? only sub i know is sub netting lol.

Re: InterVlan noob problem help

Mark Malone — Thu, 15 Feb 2018 10:13:37 GMT

Ok i dont know what book your reading off or what configuration is in place , if this is just a lab setup please provide the running config off the devices so we can see if there is something missing

Thats correct L2 device cant do it as its a l3 function but the router either needs to be in trunk mode or using sub interfaces for the design you provided by screenshot to work , thats why i provided a link to show you exactly what a router on stick design is

Re: InterVlan noob problem help

WIZARD1325 — Thu, 15 Feb 2018 17:35:33 GMT

I am drawing a blank. Says nothing about trunking here in the book

its an excercise about connecting 3 ways

1. physical router

2. subinterfaces

3. switched virtual interfaces

right now im working on lab 1.

i did everything right but there is a section in the paragraph that talks about

vlan 10 has a subnet of 192.168.10.0

i dont remember putting in any subnets just ip address on the router and computers. could this be the missing link?

Re: InterVlan noob problem help

Mark Malone — Thu, 15 Feb 2018 17:51:00 GMT

the sub interface is the trunk on the router , thats where the vlan tag gets inserted in config , so you would have as an example like belwo on the router

interface g0/0
no ip address
interface g0/0.10
encapsulation dot1q 10
ip address 192.168.10.254 255.255.255.0

Then on the switch uplink to the router
int g0/0
switchport mode trunk

whatr your doing there is whats described in the link i provided , it explains the subinterfaces and how it works when connected to a layer 2 switch

Im not sure what book your working off but without seeing what you have done in terms of configuration its difficult to assist

Re: InterVlan noob problem help

WIZARD1325 — Thu, 15 Feb 2018 18:03:19 GMT

ok so I am also noticing that I cant ping the router ether

hmmmmm.......but i can ping the computer in the vlan.....hmmmmm

Re: InterVlan noob problem help

WIZARD1325 — Thu, 15 Feb 2018 18:08:29 GMT

ok I attached the LAB

to this post hopefully that clears any confusion.

pretty straight forward

Re: InterVlan noob problem help

WIZARD1325 — Thu, 15 Feb 2018 18:09:08 GMT

the second page

Re: InterVlan noob problem help

Jon Marshall — Thu, 15 Feb 2018 18:54:59 GMT

You are not using a trunk, you are using a separate physical interface for each vlan on the router.

So using vlan 10 as example, allocate ports for PCs and the port connecting to router into vlan 10 and assign IPs to PCs and an IP to router interface from vlan 10 subnet.

The default gateway for the PCs in vlan 10 will be the IP assigned to the router interface.

Jon

Re: InterVlan noob problem help

WIZARD1325 — Thu, 15 Feb 2018 19:57:47 GMT

i did that and it didnt work

1. I cant ping the router

2. I cant ping Vlan 10 to Vlan 20

3. none can ping router

I. I can ping inside vlan 10 and between vlan 20

Re: InterVlan noob problem help

Jon Marshall — Thu, 15 Feb 2018 20:01:55 GMT

Sorry you were obviously still typing.

Post switch and router configs plus -

“show vlan brief”

from the switch.

Jon

Re: InterVlan noob problem help

Georg Pauwen — Thu, 15 Feb 2018 20:48:09 GMT

Hello,

for the sake of clarity, I recreated the lab (see attachment). Rename the .jpg to .pkt and open in Packet Tracer Version 7.1.1.

Re: InterVlan noob problem help

WIZARD1325 — Fri, 16 Feb 2018 20:43:36 GMT

ok so i figured it out. The wire from the router to the switch

needed to be trunked. I have been trunk the host to the switch LOL.

man why dont books just say that urghhhh 3 days to figure that crap out

Re: InterVlan noob problem help

WIZARD1325 — Fri, 16 Feb 2018 20:44:45 GMT

thanks for everybodys help..

now gotta practice this to memory

Re: InterVlan noob problem help

Georg Pauwen — Fri, 16 Feb 2018 21:46:10 GMT

Hello,

the link(s) between the switch and the router need to be trunks only when you use subinterfaces on the router (called router-on-a-stick), which you don't have configured. You are using the physical interfaces on the router, so the ports connecting the switch to the router need to be access ports.

Here is the correct switch and router configuration. For the sake of convenience, I have configured two DHCP pools, so if you set the PCs to DHCP, they will automatically get an IP address:

Switch

interface FastEthernet0/1
description Link to PC1
switchport access vlan 10
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/2
description Link to PC2
switchport access vlan 10
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/3
description Link to PC3
switchport access vlan 20
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/4
description Link to PC4
switchport access vlan 20
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/5
switchport access vlan 10
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/6
switchport access vlan 20
switchport mode access
spanning-tree portfast

Router

ip dhcp excluded-address 192.168.10.1
ip dhcp excluded-address 192.168.20.1
!
ip dhcp pool VLAN10
network 192.168.10.0 255.255.255.0
default-router 192.168.10.1
ip dhcp pool VLAN20
network 192.168.20.0 255.255.255.0
default-router 192.168.20.1
!
interface GigabitEthernet0/0
ip address 192.168.10.1 255.255.255.0
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.20.1 255.255.255.0
duplex auto
speed auto