Hi,

I work for an educational institute. I have limited networking knowledge. Currently our instiotute has a peer 2 peer network with static IPs. We now are facing a crunch with IPs and would like to use a DHCP server, I have persuaded my institute to use ubuntu.

Now, here is the issue
we have IP addresses from 192.168.11.0 to 192.168.11.255 with 192.168.11.250 being the gateway which runs SUSE 8

I have setup my DHCP configuration like this

# A slightly different configuration for an internal subnet.
subnet 192.168.10.0 netmask 255.255.254.0 {
range 192.168.10.3 192.168.10.250;
option domain-name-servers 202.54.1.30, 202.54.9.1;
option domain-name "abc.edu";
option routers 192.168.11.250;
option broadcast-address 192.168.11.255;
default-lease-time 600;
max-lease-time 7200;
}

I have also changed the subnet maskon the gateway to 255.255.254.0

Now when I connect a windows machine it gets the DHCP lease (192.168.10.250) but is unable to connect to the gateway? I have no idea whatsd wrong.
When i try to ping this machine from the gateway the gateway tries to access a m/c 192.168.10.2 which does not exist.

Kindly help

Another query, Our institute is wifi enabled and I would like the laptops also to user this DHCP server, In this case what should be done regarding the access points, should they be given static IPs
thanks
vijay

Could you post the output of ifconfig for your gateway and ipconfig /all for your clients?

Maybe you could do a traceroute (or tracert) from your client?

Is there any reason why you change the subnet mask to 255.255.255.254.0? I haven't done any subnetting for a while but, that would change your broadcast address to, I think, 192.168.10.252 or 251? Also if you are going to have two networks 192.168.11.0 and 192.168.10.0 the gateway for your clients has to be on the same network. You clients are on 192.168.10.0 but, your gateway is on 192.168.11.0. That's why you can't ping the router. Change the IP address that your dhcp server is giving out to 192.168.11.0

You should post how your router is set up e.g routing table, and the topology. Don't mess with the subnet masks. Keep them simple like 255.255.255.0.

What type of access points are they? If they are generic wireless routers then the WAN and LAN should be on the same network some APs don't let you do this! If not, the wireless routers will have a DHCP server which the the clients can use. The client's won't be on your 192.168.10.0 network.

So in short.

show us your topology, your swithes, router, and uplink(internet connection)

show us your routing table

Put all your clients on the same network as your gateway

give one client a static address and configuration and make sure it can access
the gateway then the internet

use those settings to create a working DHCP conf file

You misread that. His mask is 255.255.254.0. His subnet is 192.168.10.1. That gives him 192.168.10.1-192.168.11.255. His broadcast is correct. If he has a client that has a 192.168.10.x address he should be able to ping a 192.198.11.x address just fine as long as everything has the correct subnet mask because they are a single network and not 2 networks (also assuming same physical network).

That was why I wanted to see the ipconfig/ifconfig info on his clients and gateway to make sure the netmasks were correct everywhere.

hi
thnaks for your replies, unfortunately our institute does not have any network plan the network just grew and the guy who set it up is no longer there.
I have tried to redefine the problem

Hi
I am trying to get my institute's network on track. I have finally got a network diagram of my insti and I will try to describe it for you.

We have a RF connection from an ISP which flows into a modem.

The modem is connected to a cisco router (model 1721) having two ethernet ports,

Etho: ip: 203.200.166.50 Netmask 255.255.252.0

eth1: ip: 192.168.10.1

This router feeds a gateway again with two NICs

eth1: 192.168.10.2 Netmask 255.255.255.0

eth0: 192.168.11.250 netmask 255.255.255.0

This gateway is connected to a p2p network with static IPs (including wireless access points) directly connected to this PC using hubs. this PC uses Linux and we primarily use it as a proxy (Squid) and content filtering (Dansguardian)

THERE ARE NO OTHER ROUTERS PRESENT ALL COMPUTERS ARE CONNECTED WITH HUBS AT SPECIFIC LOCATIONS. THESE HUBS DO NOT HAVE AN IP

We now have a problem with respect to number of IPs as we need to accomodate around 100 more computers and i have no IPs left?


The fundamental question is which is the easiest way to get these IPs for the new computer,

Secondly we want to get a client server system in place and want to have a DHCP server, to be augmented in future with other servers for mail, file sharing etc.

I have a Ubuntu (6.06) box and have tried a few experiments.

1. Created a DHCP config the config is given below
# A slightly different configuration for an internal subnet.
subnet 192.168.10.0 netmask 255.255.254.0 {
range 192.168.10.3 192.168.10.250;
option domain-name-servers 202.54.1.30, 202.54.9.1;
option domain-name "iiswbm.edu";
option routers 192.168.11.250;
option broadcast-address 192.168.11.255;
default-lease-time 600;
max-lease-time 7200;
}

I also changed the netmask of the gateway to 255.255.254.0 and also of the DHCP server and client.


A machine next to the DHCP server is able to aquire an address but is unable to ping the gateway or the router.

A machine in a different room is not able to get the address at all.

Even in a fixed IP scenario a machine in a differnt room from the server is unable to ping the router (192.168.10.1) but a traceroute flashes this number.

My gut feeling says there is some problem with the router's config (192.168.10.1) I have no idea gow to change the parameters in a Cisco 1721 router.


Can u suggest two things.

1. A quick fix solution (any method ) to get 100 additional IPs

2. a long term solution involving DHCP ( preferrabley a step by step recommendation)

Thanks
Vijay