NetSimK ; VLAN configuration

huafist

I have another question guys.
I decided to test my knowledge of VLAN configuration using NetSimK ; however, I don't think my knowledge is what I thought it was haha.

I set up a very simple scenario: I have two switches, with two PC's on each switch. On each switch, I have a member of VLAN10 and a member of VLAN20, and I have them trunked on one of the gigabit ports. I also have a 2600 series router in the config that I was attempting router-on-a-stick with. However, I have a problem: I can ping across the VLANs, but I cannot ping the switches, nor the router's subinterfaces.

Diagram:


Switch1 Config:
switch1#show running-config
Building Configuration...

Current Configuration : 1379 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname switch1
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface FastEthernet0/1
switchport access vlan 10
!
interface FastEthernet0/2
switchport access vlan 20
!
<<Nothing plugged into the rest of the FastEthernet Ports>>
interface GigabitEthernet0/1
switchport mode trunk
!
interface GigabitEthernet0/2
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan10
ip address 192.168.0.2 255.255.255.0
no ip route-cache
!
interface Vlan20
ip address 192.168.1.2 255.255.255.0
no ip route-cache
shutdown
!
ip default-gateway 192.168.0.1
ip http server
!
line con 0
line vty 0 4
!
end

Switch 2 Config:
switch2#show running-config
Building Configuration...

Current Configuration : 1358 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname switch2
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface FastEthernet0/1
switchport access vlan 10
!
interface FastEthernet0/2
switchport access vlan 20
!
<<Nothing plugged into the rest of the FastEthernet Ports>>
interface GigabitEthernet0/1
switchport mode trunk
!
interface GigabitEthernet0/2
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan10
ip address 192.168.0.3 255.255.255.0
no ip route-cache
shutdown
!
interface Vlan20
ip address 192.168.1.3 255.255.255.0
no ip route-cache
shutdown
!
ip http server
!
line con 0
line vty 0 4
!
end

Router Config:
Router#show running-config
Building Configuration...

Current Configuration : 797
!
version 12.2
no service password-encryption
no service udp-small-servers
no service tcp-small-servers
!
hostname Router
!
!
!
!
interface FastEthernet0/0
no ip address
no ip directed-broadcast
!
interface FastEthernet0/0.10
encapsulation dot1q 10
ip address 192.168.0.1 255.255.255.0
no ip directed-broadcast
!
interface FastEthernet0/0.2
encapsulation dot1q 20
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast
!
!
interface FastEthernet0/1
no ip address
no ip directed-broadcast
shutdown
!
!
interface Serial0/0
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/1
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/2
no ip address
no ip directed-broadcast
shutdown
!
no ip classless
!
line con 0
line aux 0
line vty 0 4
!
end

help?

drkat

From just briefly looking....

Gi0/2 on SW1 isnt configured as a trunk port - show interface Gi0/2 switchport


Remember that with RoS the port connected to the router is trunked..

interface Gi0/2
switchport trunk encapsulation dot1q
switchport mode trunk

lantech

You only need one IP address per switch in whatever VLAN you want to be the management VLAN.

Did you set the encapsulation on your trunk ports in between your switches? Since you didn't specify it then it will default to ISL but your trunk to your router is using dot1q encapsulation which will cause problems.

mapletune

remember, icmp echo packets need to be able to travel both ways in order for you to ping successfully.

Your router config
interface FastEthernet0/0.10
encapsulation dot1q 10
ip address 192.168.0.1 255.255.255.0
!
interface FastEthernet0/0.2
encapsulation dot1q 20
ip address 192.168.1.1 255.255.255.0

Your Switch 1 config
Management
interface Vlan10
ip address 192.168.0.2 255.255.255.0
ip default-gateway 192.168.0.1

Your Switch 2 config
Management
interface Vlan10
ip address 192.168.0.3 255.255.255.0
shutdown
!
interface Vlan20
ip address 192.168.1.3 255.255.255.0
shutdown
no ip default-gateway

So, naturally, you can't ping Switch 2 or from Switch 2

huafist

I broke everything down and started from scratch ; here's my config commands list for all 3 devices:

Switch 1:
vlan 10
vlan 20
interface vlan10
ip address 192.168.0.2 255.255.255.0
no shut
exit
ip default-gateway 192.168.0.1
interface fa0/1
switchport access vlan 10
interface fa0/2
switchport vlan 20
interface gi0/1
switchport mode trunk (NetSimK apparently does not support the switchport trunk encapsulation command)
interface gi0/2
switchport mode trunk
exit
vtp mode server
vtp domain test.net
vtp password vlantest


Switch 2:
hostname switch2
vlan 10
vlan 20 (I know I shouldn't have to specify these when using VTP, but for the sake of not having to worry about it here, I'm doing it)
interface vlan 10
ip address 192.168.0.3 255.255.255.0
exit
ip default-gateway 192.168.0.1
interface fa0/1
switchport access vlan 10
interface fa0/2
switchport access vlan 20
interface gi0/1
switchport mode trunk
exit
vtp mode client
vtp domain test.net
vtp password vlantest

At this point, I can ping from machine-to-machine on vlans 10 and 20, but I cannot ping 192.168.0.2 (switch1).

Router Config:
interface f0/0
no ip address
no shut
interface f0/0.10
encapsulation dot1q 10 native
ip address 192.168.0.1 255.255.255.0
interface f0/0.20
encapsulation dot1q 20
ip address 192.168.1.1 255.255.255.0


At this point, I still cannot ping 192.168.0.1 from either of the PC's in vlan10, nor can I ping them from the router. If i run "show interface f0/0.10", then I get this back:
Router#show interface fa0/0.10
FastEthernet0/0.10 is up, line protocol is down Internet address is 192.168.0.1/24
MTU 1500 bytes, BW 100000 Kbit, DLY 2000 usec, rely 255/255, load 1/255
Encapsulation ARPA
ARP type: ARPA, ARP timeout 00:05:00

I set the encapsulation to dot1q ; what gives?

mapletune

I don't have access to my lab right now, but i set up a simple 1 router 1 switch 2 hosts and 2 vlan (+1 default vlan 1) packet tracer lab.

I used 2621xm and 2950 gear, and ROAS is working well.

So... it shouldn't be too hard (speaking about the commands)

Let me look over your config and see if i can spot anything else...

huafist

mapletune wrote: »

I don't have access to my lab right now, but i set up a simple 1 router 1 switch 2 hosts and 2 vlan (+1 default vlan 1) packet tracer lab.

I used 2621xm and 2950 gear, and ROAS is working well.

So... it shouldn't be too hard (speaking about the commands)

Let me look over your config and see if i can spot anything else...

Thanks.
I wouldn't think it would be too hard either ; I don't now if it's something small I'm missing, or if NetSimK is just being retarded (I had MAJOR issues with it an PPP encapsulation, and with RIP routing).

lantech

My suggestion, get a better simulator.

The problem may be that you can't set the encapsulation on the two switches. It may be defaulting to ISL instead of the dot1q like you have on your router. You might trying changing the config on the router to ISL.

huafist

lantech wrote: »

My suggestion, get a better simulator.

The problem may be that you can't set the encapsulation on the two switches. It may be defaulting to ISL instead of the dot1q like you have on your router. You might trying changing the config on the router to ISL.

I'm leaning towards the simulator being the issue as well. FWIW, you can't change the encapsulation type on the router to ISL in NetSimK ; it only supports dot1q according to the command syntax.

drkat

what does show interface gi0/2 switchport give you

huafist

drkat wrote: »

what does show interface gi0/2 switchport give you

switch1#show interface gi0/2 switchport
GigabitEthernet0/2 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is E33F.8500.101B (bia E33F.8500.101B)
MTU 1500 bytes, BW 0 Kbit, DLY 2000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 1000BaseTX
ARP type: ARPA, ARP timeout 00:05:00

drkat

yeah that sim doesnt support everything.. bleh

mapletune

I know this isn't related but...

1000/100 mismatch =p

lantech

Try finding packet tracer. I know it doesn't do absolutely everything. But you can at least do trunking and get the proper show commands to diagnose issues when the come up. Should be pretty much all you need for CCNA.

mapletune

Hey all, I spent some more time with real switches, real routers, and GNS3 as hosts for the different VLANS.

Here's my configs:

ROUTER
interface FastEthernet0
speed 100
full-duplex
no shutdown
!
interface FastEthernet0.1
encapsulation dot1Q 1
ip address 192.168.1.1 255.255.255.0
!
interface FastEthernet0.10
encapsulation dot1Q 10 native
ip address 192.168.10.1 255.255.255.0
!
interface FastEthernet0.20
encapsulation dot1Q 20
ip address 192.168.20.1 255.255.255.0
SWITCH
interface FastEthernet0/1
switchport mode access
!
interface FastEthernet0/2
switchport access vlan 10
switchport mode access
!
interface FastEthernet0/3
switchport access vlan 20
switchport mode access
!
interface FastEthernet0/24
switchport trunk native vlan 10
switchport mode trunk
speed 100
duplex full
!
interface Vlan10
ip address 192.168.10.2 255.255.255.0
no shutdown
!
ip default-gateway 192.168.10.1

=====================================

So, with this config, I got almost everything working.

Router can ping all 3 hosts and switch management int vlan 10.

Switch can ping Router's .10 .20 subint, and Hosts from VLAN 10,20
Switch cannot ping Router's .1 subint, nor ping Hosts from VLAN 1.

All hosts can ping each other and router and switch. EXCEPT Hosts from VLAN 1 cannot ping switch.

TLDR Connectivity issue between Switch management int VLAN 10 and VLAN 1 hosts/accessport my guess is that interface VLAN10 is actually in vlan 1...

can someone confirm my hunch? =D

nvm. int vlan 10 is not in vlan 1...

======

anyway, for practical purposes, huafist, don't mess with the "native" command.

Keep VLAN 1 as the native vlan and move whatever ports you don't want out of it.

Things will go much smoother

NetworkVeteran

Interestingly, on a production device today, I used that command.

switchport trunk native vlan 300
switchport trunk allowed vlan remove 300

mapletune

Practical as in, i don't think exam troubleshooting go that much in-depth =P

====

well... i got it to work =S finally

...


So, basically, on the switch, you can't have 2 int vlan ip addresses

I had this:

int vlan 1
ip address 192.168.1.2 255.255.255.0
shut
int vlan 10
ip address 192.168.10.2 255.255.255.0
no shut

ip default-gateway 192.168.10.1 (<- which i would switch in-between with 192.168.1.1 depending on which int vlan 1/10 i was testing and had it in no shut)

so after deleting ip address on vlan 1, everything works.

fun little problem... i guess

cheers,

lantech

That's because a VLAN doesn't need an IP address. In fact the switch itself doesn't require an IP address to work. The IP address is so that you can telnet into the switch and manage the switch from a remote location.

huafist

So I'm not crazy? haha
I'm going to set this up in GNS3 when I get to work and see if I can make it work there.

mapletune

To be honest, this was one of the times I wish I knew how to use packet sniffers.

Like, i know what caused the connectivity issue now, but, i still don't know why.

=S i need to learn how to use Wireshark soon...

huafist

Ok, so I set this up in GNS3, but no hosts. I set up 3 routers - one as a router and two as 16 port switches. I can ping from switch 1 (which is the vtp server with VLAN 10 and 20 configured on it, VLAN10 is up with IP 192.168.0.2/24). To subinterface fa0/0.10 (192.168.0.1) on the router, but I can't communicate with 192.168.1.1 (subinterface fa0/0.20), even though I have RIP routing enabled and the networks added. show ip route shows both networks as enabled in the router, as well. I configured vlan1 on the second router with the IP 192.168.1.3/24, and connected it to an unused port on switch 1 (attempting to use it as a host, no VLAN trunking, etc on it), but I can't ping 192.168.1.1 from it either.

With RIP enabled and communication with .0.1 from switch 1, I would expect to be able to ping .1.1 from switch 1 through routing?

mapletune

to be honest, using gns3 routers+nm-16esw to emulate cisco switches is outside my area of knowledge. =/ sorry that i can't help.

what i usually do is use hardware switches connected to gns3 virtual routers. but this time, i actually used all real hardware to make sure i got everything correct.

so, what you want to do is definitely possible. good luck =]

NetworkVeteran

huafist wrote: »

Ok, so I set this up...

Hua, when you have a problem post your full configs and list how the devices are interconnected (eg: R1::f0/0 <=> R2::f1/0). It's easier to debug real configurations than long verbal descriptions. Those configs will be more precise and not miss details.

in GNS3, but no hosts. I set up 3 routers - one as a router and two as 16 port switches. I can ping from switch 1 (which is the vtp server with VLAN 10 and 20 configured on it, VLAN10 is up with IP 192.168.0.2/24). To subinterface fa0/0.10 (192.168.0.1) on the router, but I can't communicate with 192.168.1.1 (subinterface fa0/0.20), even though I have RIP routing enabled and the networks added. show ip route shows both networks as enabled in the router, as well. I configured vlan1 on the second router with the IP 192.168.1.3/24, and connected it to an unused port on switch 1 (attempting to use it as a host, no VLAN trunking, etc on it), but I can't ping 192.168.1.1 from it either.

With RIP enabled and communication with .0.1 from switch 1, I would expect to be able to ping .1.1 from switch 1 through routing?

Let me try to translate--

What the above words mean wrote:

Switch 1

---

vlan 10
vlan 20
int vlan 10
_ip address 192.168.0.2 255.255.255.0

Router 1
_______
int fastethernet0/0
int fastethernet0/0.10
_encapsulation dot1q 10
_ip address 192.168.0.1 255.255.255.0
int fastethernet0/0.20
_encapsulation dot1q 10
_ip address 192.168.1.1 255.255.255.0
router rip
_network 192.168.0.0
_network 192.168.1.0

Router 2
_______
vlan 1
int fastethernet1/0
_switchport mode access
_switchport access vlan 1
int vlan 1
_ip address 192.168.1.3 255.255.255.0

Do you see how incomplete the above is? Even after spending time translating your words into a virtual configuration, there are a plethora of things you could've done wrong.

For example--
1. You might've forgotten to no shut your interfaces.
2. You only mention RIP on Router1; routing protocols are intended to share information between routers, so enabling it on one router isn't particularly effective.
3. You don't mention how you're telling Switch1 to get its traffic to 192.168.1.1.
4. You put two devices on the same subnet (192.168.1.x) but on different VLANs.
5. You don't mention the router having a subinterface on vlan 1.

Anyway, post full configs, and we can probably pinpoint your real issue rather than speculating on all the things that someone could possibly get wrong.

NetworkVeteran

Maple, the configs you posted worked fine on my devices--provided, and these are important, I disabled IP routing on the switch and ensured those VLANs were actually created.

I had this:

int vlan 1
ip address 192.168.1.2 255.255.255.0
shut

so after deleting ip address on vlan 1, everything works.

This was not in the configuration you posted before. If you can post the exact configuration causing troubles we might be able to explain it. Adding the above, alone, to the previous configuration you posted does not pose any problems on my setup. Alternatively, if you use GNS3 for the routers / switches, Wireshark is built in, and yes it's wonderful for debugging.

lantech

Also, a good build philosophy is to go one step at a time. Get one part of your network working then work on the next part.

mapletune

Thank you NetVet =D

I think your advice is really really timely. us being relative newbies here.

I have a problem "assuming/taking for granted" that other people know what i'm talking about. And you're comment about posting the exact config + connections really hit my weakness in the eye =D haha

So yes, thanks for the practical advise. I'll keep it in mind.

---

as for full configs, I don't have them anymore because i shut down my lab O_O!! haven't really started labbing methodologically.. so I don't really save any of my topologies or configs. I just start blank everytime and lab whatever I found interesting, like this thread.

I might try to reproduce my problem soon though mostly, inspired by your willingness and helpfulness! haha, i didn't think anyone would actually throw my configs into a machine. I was just trying to illustrate the situation.

----

NetworkVeteran,
I went back to read your response; you said you disabled ip routing on your switch, but my switches are 2950's. I thought they don't touch Layer 3. However, what you are saying makes total sense, because as soon as I removed conflicting (albeit shutdown) ip, it all worked. So, the problem had to have been related to IP's and interface vlan. I just assumed with 2950's i didn't have to worry about L3 (only for management).

huafist

Sorry for the delay, I got held up here at work. Here are the configs:

Router:
Router1#show running-config
Building configuration...

Current configuration : 1297 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
!
no ip domain lookup
ip domain name lab.local
!
multilink bundle-name authenticated
!
interface FastEthernet0/0
no ip address
speed 100
full-duplex
!
interface FastEthernet0/0.10
encapsulation dot1Q 10 native
ip address 192.168.0.1 255.255.255.0
!
interface FastEthernet0/0.20
encapsulation dot1Q 20
ip address 192.168.1.1 255.255.255.0
!
interface Serial0/0
ip address 10.0.0.1 255.255.255.248
clock rate 2000000
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet1/0
no ip address
shutdown
duplex auto
speed auto
!
router rip
version 2
network 10.0.0.0
network 192.168.0.0
network 192.168.1.0
!
ip forward-protocol nd


Switch 1(VLANS):
R2#show running-config
Building configuration...

Current configuration : 1639 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
!
no ip domain lookup
ip domain name lab.local
!
multilink bundle-name authenticated
!
interface FastEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet1/0
switchport access vlan 10
!
interface FastEthernet1/1
switchport access vlan 20
!
interface FastEthernet1/15
switchport trunk native vlan 10
switchport mode trunk
duplex full
speed 100
!
interface Vlan1
no ip address
!
interface Vlan10
ip address 192.168.0.2 255.255.255.0
!
interface Vlan20
no ip address
!
ip default-gateway 192.168.0.1
ip forward-protocol nd
!

Switch2 (Just a vlan configured with an IP ; trying to simulate a host instead of another VLAN'd switch)
R3#show running-config
Building configuration...

Current configuration : 1532 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
ip cef
!
!
!
!
no ip domain lookup
ip domain name lab.local
!
multilink bundle-name authenticated
!
interface FastEthernet1/14
switchport access vlan 20
duplex full
speed 100
!
interface FastEthernet1/15
!
interface Vlan1
no ip address
!
interface Vlan20
ip address 192.168.1.3 255.255.255.0
!
ip default-gateway 192.168.1.1
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 192.168.1.1
!

lantech

For the first switch don't you have to set the encapsulation. I know you're trying to use the router as a switch but I don't think routers auto-negotiate the encapsulation protocols. That will prevent trunking in between the two devices.

NetworkVeteran

lantech wrote: »

I know you're trying to use the router as a switch but I don't think routers auto-negotiate the encapsulation protocols. That will prevent trunking in between the two devices.

GNS3 can emulate an actual switch, specifically the one in an EtherSwitch Module. You use normal Catalyst IOS commands to configure them, not router commands. Like 2950s, they only support 802.1Q encapsulation and no special configuration is required to specify that.

Huafist, when I load your configs, Switch1 can't ping 192.168.1.1. That is, until I make a one-line change! As a hint for you, the fix is related to one of the error possibilities I previously mentioned--

NetworkVeteran wrote:

1. You might've forgotten to no shut your interfaces.
2. You only mention RIP on Router1; routing protocols are intended to share information between routers, so enabling it on one router isn't particularly effective.
3. You don't mention how you're telling Switch1 to get its traffic to 192.168.1.1.
4. You put two devices on the same subnet (192.168.1.x) but on different VLANs.
5. You don't mention the router having a subinterface on vlan 1.

huafist

NetworkVeteran wrote: »

GNS3 can emulate an actual switch, specifically the one in an EtherSwitch Module. You use normal Catalyst IOS commands to configure them, not router commands. Like 2950s, they only support 802.1Q encapsulation and no special configuration is required to specify that.

Huafist, when I load your configs, Switch1 can't ping 192.168.1.1. That is, until I make a one-line change! As a hint for you, the fix is related to one of the error possibilities I previously mentioned--

Is the error in switch1's config or in the router's config?

I was under the impression that due to the fact only one interface on a switch should have an IP, that switch1 wouldn't be able to ping 192.168.1.1 - that is, without routing through 192.168.0.1, which I thought it would since its default gateway is .0.1. I was also under the impression that since switch2 is connected to a port that's assigned to VLAN20, and the subinterface fa0/0.20 on the router is also specified as a member of VLAN20 and both have IPs in the 192.168.1.0/24 network, that it should be able to ping it across the trunk without any routing?

lantech

lantech wrote: »

For the first switch don't you have to set the encapsulation. I know you're trying to use the router as a switch but I don't think routers auto-negotiate the encapsulation protocols. That will prevent trunking in between the two devices.

I didn't realize that GNS3 emulated switches as well as routers and that 2950s don't support ISL. DOH