How can I connect routers via switch?

[chunhyungjoon]

first, sorry for silly question! I'm Korean student studying network at school.

My school has no DHCP server and I got these IPs from school. : 192.168.128.x / 255.255.0.0 / gateway:192.168.1.254

I have Cisco 2811, and want to connect to school network.

Simple topology ---

ISP - Local Office of Education (firewall) - School Router - switches(with no setting) - My router

---------------------------

yeah , I think it is impossible to link mine to school's without configure school's manualy....

but I want to know how to!

Do I have to use routing protocol? or other work?

Thanks!

[Mahesh Gohil]

Hi,

If switch has no setting thet means it is working as a HUB..means everything coming on one end is passsing to all other ports.

you may configure ip to the interface connecting towards switch and in addition you can configure default route pointing

towards default gateway.

int

ip address 192.168.128.2 / 255.255.0.0

ip route 0.0.0.0 0.0.0.0 192.168.1.254

but we need more clarity as how you are going to use this router. where the users will be connected...

Regards

Mahesh

[chunhyungjoon]

Thanks, mahesh.

I've tried ip route 0.0.0.0 0.0.0.0 192.168.1.254

The result, failed. Can't ping to 192.168.1.254 (from the labtop) . I think I didn't make some required configurations.

Show ip route result below:

-----------------------

Cplus#sh ip route

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

       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 192.168.1.254 to network 0.0.0.0

S*   0.0.0.0/0 [1/0] via 192.168.1.254

C    192.168.0.0/16 is directly connected, FastEthernet0/1

----------------------

The attactched picture shows the specified topology.

Thanks!

[Mahesh Gohil]

Hi,

From diagram it shows that you got 192.168.128.x and not whole /16. Why there is no ip on fa0/0 of your 2811 router. You need

ip on fa0/0 then only you laptop will talk to 2811 router.

you need now two subnets (divide existing 192.168.128.x into two parts)

> one towards school router (/30 is sufficient)

> next for laptop/Ap to 2811 router (fa0/0). (keep rest from 192.168.128.x)

hope this is useful

Regards

Mahesh

[chunhyungjoon]

Thanks for replying,

Sorry. Can you explain again?

I should set ip address to 192.168.x.x /16 in our school or I cannot use internet.

And I use 192.168.128.x, and I don't know which subnet to use, (/30 or /24? IOS says /30 is bad mask on 192.168.128.11) and where to.

What IP and subnet do I have to use for f0/0~1?

[Mahesh Gohil · Accepted solution]

Hi,

sorry for the lack of clarity in my last reply.

If you are having /16 pool given by school. use the subnets as below

> Fa0/1..use 192.168.1.11 255.255.255.0
> Fa0/0..use 192.168.128.1 255.255.128.0

Give gateway of 192.168.128.1 to laptop.

Regards

Mahesh

[chunhyungjoon]

Thankyou very much, Mahesh !

Successfully connected, works great.

In Korea it's 8:46 PM now but you must be very tired cause there would be 5:46 AM , aren't you?

Sorry for my silly questions ... I think I have to study a lot. (English and networking)

If you don't mind, could you explain about these subnets?

Best regards, (<- is this okay to use in ....kind of semi formal letters? I'm not good at English....)

Hyung Joon