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Community Member

Inter VLAN Routing Help Needed

I'm attemtping to setup a small lab.

I have one 3550 SMI

I have several VLANs defined, see config below. I have a DHCP server - 10.10.10.2

And a route to the rest of the network via 192.168.0.90.

From the switch, I can ping the VLAN interfaces (as long as there's a device on the VLAN). Howver, there are two problems:

1- DHCP doesn't work, the discovery never makes it to the server

2. I'm unable to ping clients (which are statically addressed) in the other VLANS.

The routing table looks correct.

From the switch I can ping the outside world.

My config is attached.

I would sincerely appreciate any help.

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: Inter VLAN Routing Help Needed

Hector,

This is clearly a L2 issue. Where are the server and client connected. I only see 3 access port in vlan1010 (fa0/2,fa0/3,fa0/4) and these 3 ports are down in the output you provided. fa0/1 is a trunk port and carries vlan 1010. Are the server and client connected to another switch? If so, is the trunk port up?

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
10 REPLIES
Hall of Fame Super Blue

Re: Inter VLAN Routing Help Needed

Okay, your "sh ip route" does not show a directly connected route for 10.10.10.x. This i suspect is why you can't ping the DHCP server.

Can you post output of "sh ip int brief"

Jon

Community Member

Re: Inter VLAN Routing Help Needed

Jon, thanks for the fast response, see below. I seem to have a route to VLAN 1010, which has an IP of 10.10.10.10.

And, I confirmed that each client uses its respective VLAN IP as the Default Gway. Thanks again.!

meru#sho ip interface brief

Interface IP-Address OK? Method Status Protocol

Vlan1 10.10.1.1 YES manual up down

Vlan192 192.168.0.90 YES manual up down

Vlan1010 10.10.10.10 YES manual up down

Vlan1020 10.10.20.10 YES manual up up

Vlan1030 10.10.30.10 YES manual up up

Vlan1040 10.10.40.10 YES manual up down

FastEthernet0/1 unassigned YES unset down down

FastEthernet0/2 unassigned YES unset down down

FastEthernet0/3 unassigned YES unset down down

FastEthernet0/4 unassigned YES unset down down

FastEthernet0/5 unassigned YES unset up up

FastEthernet0/6 unassigned YES unset down down

FastEthernet0/7 unassigned YES unset down down

FastEthernet0/8 unassigned YES unset down down

FastEthernet0/9 unassigned YES unset down down

FastEthernet0/10 unassigned YES unset down down

FastEthernet0/11 unassigned YES unset up up

FastEthernet0/12 unassigned YES unset down down

FastEthernet0/13 unassigned YES unset down down

FastEthernet0/14 unassigned YES unset down down

FastEthernet0/15 unassigned YES unset down down

FastEthernet0/16 unassigned YES unset down down

FastEthernet0/17 unassigned YES unset down down

FastEthernet0/18 unassigned YES unset down down

FastEthernet0/19 unassigned YES unset down down

FastEthernet0/20 unassigned YES unset down down

FastEthernet0/21 unassigned YES unset down down

FastEthernet0/22 unassigned YES unset down down

FastEthernet0/23 unassigned YES unset down down

FastEthernet0/24 unassigned YES unset down down

GigabitEthernet0/1 unassigned YES unset down down

GigabitEthernet0/2 unassigned YES unset down down

Purple

Re: Inter VLAN Routing Help Needed

Vlan 1010 (where the dhcp server is supposedly attached) does not look like it is up so the server would not be able to be reached. In your routing table there is also no connected route for vlan 1010 because it is up/down. What you posted is not the route table it is a interface listing , there is no route for 10.10.10.X in the route table. As far as clients i would check things like make sure the windows firewall is turned off . Make sure all the gateways on the clients point to the correct SVI address on the 3550 for the given vlan they are attached to. Note below what you posted , there is no route for 10.10.10.X because the SVI for 1010 is in a up/down state.

10.0.0.0/24 is subnetted, 3 subnets

C 10.10.20.0 is directly connected, Vlan1020

C 10.10.30.0 is directly connected, Vlan1030

C 10.10.40.0 is directly connected, Vlan1040

C 192.168.0.0/24 is directly connected, Vlan192

S* 0.0.0.0/0 [1/0] via 192.168.0.1

meru#ping 4.2.2.1

Community Member

Re: Inter VLAN Routing Help Needed

Thanks Glen. Below is an updated routing table and interface status. This all looks good. Except, I see my VLAN 1 is down, don't kwno why. Again, any ideas are appreciated.

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.0.1 to network 0.0.0.0

10.0.0.0/24 is subnetted, 4 subnets

C 10.10.10.0 is directly connected, Vlan1010

C 10.10.20.0 is directly connected, Vlan1020

C 10.10.30.0 is directly connected, Vlan1030

C 10.10.40.0 is directly connected, Vlan1040

C 192.168.0.0/24 is directly connected, Vlan192

S* 0.0.0.0/0 [1/0] via 192.168.0.1

meru#sho ip interface brief

Interface IP-Address OK? Method Status Protocol

Vlan1 10.10.1.1 YES manual up down

Vlan192 192.168.0.90 YES manual up up

Vlan1010 10.10.10.10 YES manual up up

Vlan1020 10.10.20.10 YES manual up up

Vlan1030 10.10.30.10 YES manual up up

Vlan1040 10.10.40.10 YES manual up up

Community Member

Re: Inter VLAN Routing Help Needed

Some more details:

I put a PC (10.10.10.13) in VALN 1010, with the DHCP server(10.10.10.2), the PC obtains an IP address via DHCP.

Pings from client to server -- work

Pings form server to slient -- work

Pings from client to def. gway 10.10.10.10) -- fail

Pings from server to def. gway (10.10.10.10) -- fail

pings from router to client 10.10.10.13 fail

pings from router to server 10.10.10.2 fail

pings from router to 10.10.10.10-- work

Cisco Employee

Re: Inter VLAN Routing Help Needed

Hector,

This is clearly a L2 issue. Where are the server and client connected. I only see 3 access port in vlan1010 (fa0/2,fa0/3,fa0/4) and these 3 ports are down in the output you provided. fa0/1 is a trunk port and carries vlan 1010. Are the server and client connected to another switch? If so, is the trunk port up?

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Community Member

Re: Inter VLAN Routing Help Needed

My bad, it was a simple addressing issue on one of the clients. I can now ping from / to everywhere.

Now on to my next challenge -- DHCP

I've setup IP Helper addresses on each VLAN, all pointing to the DHCP server 10.10.10.2 which is in VLAN 1010. However, the only client to obtain an address is the client in the same VLAN (1010) as the DHCP server.

I've turned on a sniffer on the DHCP server, the only DHCP traffic is see is that which comes from VLAN 1010.

IP UDP debugs on the router show the broadcasts with no reply.

Any suggestions?

Cisco Employee

Re: Inter VLAN Routing Help Needed

Hector,

The issue could be that the defaut gateway is not set on the DHCP server.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Hall of Fame Super Gold

Re: Inter VLAN Routing Help Needed

In a separate post Hector described his problem with DHCP and then updated it to explain that he solved the problem with DHCP when he enabled service dhcp.

HTH

Rick

Cisco Employee

Re: Inter VLAN Routing Help Needed

Thanks for the heads-up Rick.

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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