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Inter-Vlan Routing for 3750x

jaydenle
Level 1
Level 1

Hi Everyone,

I am a cisco newbie and would like to seek some professional advice on setting up intervlan routing on my cisco 3750x. I recently purchase this switch and has setup vlan 2 under subnet 192.168.2.0/24, and has enable ip routing so that it can communicate with vlan 1(default) on subnet 192.168.1.0/24. So far i have setup vlans, routing on the L3 device but still having issue communicating between the vlans. below is my vlan details and static routing.

Vlan1 is up, line protocol is up

  Hardware is EtherSVI, address is f0f7.5541.c6c0 (bia f0f7.5541.c6c0)

  Internet address is 192.168.1.252/24

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive not supported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:00, output 00:00:00, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 7000 bits/sec, 7 packets/sec

  5 minute output rate 1000 bits/sec, 1 packets/sec

     2311888 packets input, 180257387 bytes, 0 no buffer

     Received 0 broadcasts (15483 IP multicasts)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     5536 packets output, 586891 bytes, 0 underruns

     0 output errors, 2 interface resets

     0 output buffer failures, 0 output buffers swapped out

Vlan2 is up, line protocol is up

  Hardware is EtherSVI, address is f0f7.5541.c6c3 (bia f0f7.5541.c6c3)

  Internet address is 192.168.2.254/24

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive not supported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:00, output 00:05:56, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     23624 packets input, 2423692 bytes, 0 no buffer

     Received 0 broadcasts (44 IP multicasts)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     2768 packets output, 186098 bytes, 0 underruns

     0 output errors, 2 interface resets

     0 output buffer failures, 0 output buffers swapped out

C    192.168.1.0/24 is directly connected, Vlan1

C    192.168.2.0/24 is directly connected, Vlan2

S*   0.0.0.0/0 [1/0] via 192.168.255.1

S    192.168.0.0/16 [1/0] via 192.168.1.254

Have i done something incorrectly? Truly appreciate your valuable responses.

1 Accepted Solution

Accepted Solutions

Hello Jayden,

if Vlan2/192.168.2./024 subnet is defined only on C3750X you need a static route on the router like

Router:

config t

ip route 192.168.2.0 255.255.255.0 192.168.1.252

in similar way you will need a static route on router for each new Vlan/IP subnet defined only on the C3750x.

In this way regardless of default gateway settings on the hosts of Vlan1 they will be able to reach all the new IP subnets.

Hope to help

Giuseppe

View solution in original post

10 Replies 10

cadet alain
VIP Alumni
VIP Alumni

Hi,

Vlan1 is up, line protocol is up

  Hardware is EtherSVI, address is f0f7.5541.c6c0 (bia f0f7.5541.c6c0)

  Internet address is 192.168.1.252/24     

Have you set default gateway of hosts in vlan 1 as this 192.168.1.252 ?

Can your hosts ping their default gateway? Can your hosts ping the other SVI IP ?

Regards.

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

Thanks for your reply Alain,

192.168.1.252/24 is the ip address and default gateway i assigned to the switch throught the Express setup. The actual default gateway for the subnet 1 network is 192.168.1.254/24. When i set up hosts on vlan 1 on this switch it can ping all hosts on the network fine excepted for hosts on the vlan 2 i created within the 3750x. And vice versa, any devices on the local 2 subnet cannot ping anything else besides 192.168.2.254/24 and 192.168.1.252/24. Thanks for your help.

Hi,

.252 is the IP address of Vlan1 interface which should be the default gateway for hosts in vlan1( subnet 192.168.1.0/24) and not .254 as you say you have configured.

Change your hosts default gateway to point to this Vlan interface IP and it should work.

Regards.

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

Hi Alain,

Sorry for the confusion, i should have mentioned that the 192.168.1.254/24 is the ip address of my existing router hence the default gateway for the 1 subnet. What I am trying to do is assigning the 192.168.1.252 ip to the switch and create vlans on it to expand my network. Should i be assigning that ip (192.168.1.252) to the switch interface instead and use that that interface as default gateway for the vlan? Thanks.

Hello Jayden,

if Vlan2/192.168.2./024 subnet is defined only on C3750X you need a static route on the router like

Router:

config t

ip route 192.168.2.0 255.255.255.0 192.168.1.252

in similar way you will need a static route on router for each new Vlan/IP subnet defined only on the C3750x.

In this way regardless of default gateway settings on the hosts of Vlan1 they will be able to reach all the new IP subnets.

Hope to help

Giuseppe

Hi Giuseppe,

When I enter this static route it come back with the following message

Cisco3750x(config)#ip route 192.168.2.0 255.255.255.0 192.168.1.252

%Invalid next hop address (it's this router)

Thanks.

Hi,

if you want to do intervlan routing with the switch then you should use 192.168.1.252 which is configured on your

SVI( interface vlan 1) as the default gateway for the hosts in this vlan.

you can use the IP address of the router if using it as a router on a stick as default gateway but this doesn't seem to be your case.

post your topology so we know where is the router, if it is connected to switch and serves as border router  for internet?

Regards.

Alain

Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

Hi Alain,

Here is the topology of my switches, and router, the 3750G is the only switch that holds all the current vlan and ideally i like to have the new 3750x setup with vlan for redundancy. Thanks

Hi

Kindly connect an host to an access port of the switch with  vlan specified as resp.

as example

switch#: int fa 3/1

switchswitchport mode access

switchswitchport access vlan 2

connect a PC to int fa 3/1 and assign an IP in vlan2 subnet

Below is an example for the Host configuration

Host: 192.168.2.1

subnet: 255.255.255.0

Gateway: 192.168.2.254

By this an host of an Int fa 3/1 will be able to reach on the other vlans.

If you have any issues with this let me know the output from the host end.

as

open command prompt -->> Ipconfig

pjmonline
Level 1
Level 1

You need the static route on the router at 192.168.1.254.

Config t

Ip route 192.168.2.0 255.255.255.0 192.168.1.252

This will route traffic to vlan2 thru your router instead of the 3750 switch doing inter vlan routing. For vlan 2 the default gateway will be the ip address of the SVI of vlan 2 on the switch. The switch will route the traffic from vlan 2 to vlan 1. Not sure what your router is at 192.168.1.254 but if you can change the default gateway on the clients of vlan 1 to 192.168.1.252 then the switch can route traffic much faster than the router.

Sent from Cisco Technical Support iPhone App

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