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Communicating between 2 VLANs

 
 
Norman Zhang
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      08-07-2004
Hi,

I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
route packets between 2 VLANs. Default gateway on C3550 is 192.168.11.1
and IP routing is enabled. However I can't seem to be able to ping from
192.168.99.1 to 192.168.11.5. Could someone please give me a few pointers.

Regards,
Norman

internet
|
*---* *---*
| | | | 192.168.11.5/26
*---* *---* gw: 192.168.11.1
| 192.168.11.1/26 |
|--------------------*
| 192.168.11.4/26 (VLAN2)
*---*
| | gw: 192.168.11.1
*---*
| 192.168.99.1/24 (VLAN1)
|
|
*---* 192.168.99.2/24
| | gw: 192.168.99.1
*---*
 
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slipstream_242
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Posts: n/a
 
      08-07-2004
are you using a router connected to the switch? the router is used to route
packets between vlans


"Norman Zhang" <> wrote in message
news:H0%Qc.63754$T_6.29723@edtnps89...
> Hi,
>
> I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
> route packets between 2 VLANs. Default gateway on C3550 is 192.168.11.1
> and IP routing is enabled. However I can't seem to be able to ping from
> 192.168.99.1 to 192.168.11.5. Could someone please give me a few pointers.
>
> Regards,
> Norman
>
> internet
> |
> *---* *---*
> | | | | 192.168.11.5/26
> *---* *---* gw: 192.168.11.1
> | 192.168.11.1/26 |
> |--------------------*
> | 192.168.11.4/26 (VLAN2)
> *---*
> | | gw: 192.168.11.1
> *---*
> | 192.168.99.1/24 (VLAN1)
> |
> |
> *---* 192.168.99.2/24
> | | gw: 192.168.99.1
> *---*



 
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none
Guest
Posts: n/a
 
      08-07-2004
VLANs divide a network as if you had two or more switches.

*---* *---*
| | | |
*---* *---*
VLAN1 VLAN2

You need a router if you want traffic to pass between the VLANs.

Some high end switches have router modules in them or as an option that can
be used to route between the VLANS using one box.


"Norman Zhang" <> wrote in message
news:H0%Qc.63754$T_6.29723@edtnps89...
> Hi,
>
> I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
> route packets between 2 VLANs. Default gateway on C3550 is 192.168.11.1
> and IP routing is enabled. However I can't seem to be able to ping from
> 192.168.99.1 to 192.168.11.5. Could someone please give me a few pointers.
>
> Regards,
> Norman
>
> internet
> |
> *---* *---*
> | | | | 192.168.11.5/26
> *---* *---* gw: 192.168.11.1
> | 192.168.11.1/26 |
> |--------------------*
> | 192.168.11.4/26 (VLAN2)
> *---*
> | | gw: 192.168.11.1
> *---*
> | 192.168.99.1/24 (VLAN1)
> |
> |
> *---* 192.168.99.2/24
> | | gw: 192.168.99.1
> *---*




 
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Christoph Weber-Fahr
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Posts: n/a
 
      08-07-2004
Norman Zhang wrote:

> I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
> route packets between 2 VLANs. Default gateway on C3550 is 192.168.11.1
> and IP routing is enabled. However I can't seem to be able to ping from
> 192.168.99.1 to 192.168.11.5. Could someone please give me a few pointers.


Cisco provieds excessive and excellent dosumentation for their hardware
on their web site.

Why don't you go there and read that ? There is a really long chapter
"Configuring IP unicast Routing" for your switch, in the Catalyst 3550
Switch Software Configuration Guide, which has drawings, examples,
step-by-step instructions etc. (That same guide is also on the CD
you got with the switch)

Go read that. Build a configuration. Then come back and tell what
did not work. Tell what you did.

A newsgroup is not a replacement for documentation.

Regards

Christoph Weber-Fahr


 
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JR
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Posts: n/a
 
      08-08-2004
Pray tell, what is a newsgroup for?



"Christoph Weber-Fahr" <> wrote in message
news:cf2mdq$v80$06$...
> Norman Zhang wrote:
>
> > I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
> > route packets between 2 VLANs. Default gateway on C3550 is 192.168.11.1
> > and IP routing is enabled. However I can't seem to be able to ping from
> > 192.168.99.1 to 192.168.11.5. Could someone please give me a few

pointers.
>
> Cisco provieds excessive and excellent dosumentation for their hardware
> on their web site.
>
> Why don't you go there and read that ? There is a really long chapter
> "Configuring IP unicast Routing" for your switch, in the Catalyst 3550
> Switch Software Configuration Guide, which has drawings, examples,
> step-by-step instructions etc. (That same guide is also on the CD
> you got with the switch)
>
> Go read that. Build a configuration. Then come back and tell what
> did not work. Tell what you did.
>
> A newsgroup is not a replacement for documentation.
>
> Regards
>
> Christoph Weber-Fahr
>
>



 
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PES
Guest
Posts: n/a
 
      08-08-2004

"JR" <> wrote in message
news:NgfRc.316079$%...
> Pray tell, what is a newsgroup for?
>


To help people help themselves.


 
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Scooby
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      08-08-2004
The 3550 is a layer 3 switch, which means it does route - all you need is to
make sure ip routing is turned on, and you apparently have. I suspect that
your traffic is getting to the destination, but the return traffic is not
making it to you. Which would mean that you don't have the correct route on
the 192.168.11.1 back to 192.168.99.1. Or, perhaps, there is an access-list
getting in the way. But, I'd try a tracert both ways as a first step. A
sniffer at different points in the network would help too.

Hope that helps,

Jim


"slipstream_242" <> wrote in message
news:yT3Rc.312$...
> are you using a router connected to the switch? the router is used to

route
> packets between vlans
>
>
> "Norman Zhang" <> wrote in message
> news:H0%Qc.63754$T_6.29723@edtnps89...
> > Hi,
> >
> > I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
> > route packets between 2 VLANs. Default gateway on C3550 is 192.168.11.1
> > and IP routing is enabled. However I can't seem to be able to ping from
> > 192.168.99.1 to 192.168.11.5. Could someone please give me a few

pointers.
> >
> > Regards,
> > Norman
> >
> > internet
> > |
> > *---* *---*
> > | | | | 192.168.11.5/26
> > *---* *---* gw: 192.168.11.1
> > | 192.168.11.1/26 |
> > |--------------------*
> > | 192.168.11.4/26 (VLAN2)
> > *---*
> > | | gw: 192.168.11.1
> > *---*
> > | 192.168.99.1/24 (VLAN1)
> > |
> > |
> > *---* 192.168.99.2/24
> > | | gw: 192.168.99.1
> > *---*

>
>



 
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Lars Christensen
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Posts: n/a
 
      08-08-2004
Norman Zhang <> wrote in
news:H0%Qc.63754$T_6.29723@edtnps89:

> Hi,
>
> I've a C3550 switch that is segmented into 2 VLANs. I liked to able to
> route packets between 2 VLANs. Default gateway on C3550 is
> 192.168.11.1 and IP routing is enabled. However I can't seem to be
> able to ping from 192.168.99.1 to 192.168.11.5. Could someone please
> give me a few pointers.
>
> Regards,
> Norman
>


Hi Norman

What does "Show int desc" tell you... Are the VLANs up'n'runnin?
Are the VLANs in your VLAN database (show vlan database)?

Cheers Lars
 
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Norman Zhang
Guest
Posts: n/a
 
      08-11-2004
> The 3550 is a layer 3 switch, which means it does route - all you need is to
> make sure ip routing is turned on, and you apparently have. I suspect that
> your traffic is getting to the destination, but the return traffic is not
> making it to you. Which would mean that you don't have the correct route on
> the 192.168.11.1 back to 192.168.99.1. Or, perhaps, there is an access-list
> getting in the way. But, I'd try a tracert both ways as a first step. A
> sniffer at different points in the network would help too.


Thanks Jim. You are correct, echo reply is dropped by 192.168.11.1. I
have fixed the problem by adding a static route to 192.168.11.5.

Regards,
Norman
 
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Pete Mainwaring
Guest
Posts: n/a
 
      08-11-2004
Norman Zhang <> wrote in message news:<xziSc.1284$fz2.162@edtnps89>...
> > The 3550 is a layer 3 switch, which means it does route - all you need is to
> > make sure ip routing is turned on, and you apparently have. I suspect that
> > your traffic is getting to the destination, but the return traffic is not
> > making it to you. Which would mean that you don't have the correct route on
> > the 192.168.11.1 back to 192.168.99.1. Or, perhaps, there is an access-list
> > getting in the way. But, I'd try a tracert both ways as a first step. A
> > sniffer at different points in the network would help too.

>
> Thanks Jim. You are correct, echo reply is dropped by 192.168.11.1. I
> have fixed the problem by adding a static route to 192.168.11.5.
>
> Regards,
> Norman


Norman,

Sorry to state the obvious (and tell me to sod off if I am insulting
your intelligence), but the devices on the two VLANs will have
different default gateways and it was just that you only made mention
of the one def g/w 192.168.11.1 in your original question.

The devices on 192.168.11.0 network will have the 192.168.11.1 router
as the def g/w and devices on the 192.168.99.0 network will have
192.168.99.1 as the def g/w. I hope I have got the router addresses
right - I was having trouble deciphering your diagram as is not
formatted properly on the view I have of it.

What was the exact static route that you added? I was also having
trouble working out how that route solved the problem.

Pete
 
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