weird network problem in ubuntu

[amitava82]

I have this strange problem. first I'll give the facts then the problem.

my college wifi network assign ip address using DHCP.
DHCP assigned ips are in rage of 192.168.0.0 to 192.168.1.0
proxy server is 192.168.1.2
for some weird reason DHCP assigned IP addresses are blocked for net. only ips in rage of 192.168.15.0 works for internet. so i set ip address manually.

now here is the problem. for obvious reason DHCP assigned ip address won't work, so i assign ip address manually for wireless card eth1. Say if i assign ip address to 192.168.15.244 and ping 192.168.1.2 i'm getting error msg "Network Unreachable". but other computers in ip ranges 192.168.15.0 are responding to ping. now if I assign ip address to 192.168.1.244 then it pings successfully to the proxy server. but internet does not work in 192.168.1.0 ip ranges as they are blocked. same configuration in WIndows XP i.e., 192.168.15.244 can ping successfully the proxy server and can browse internet. even my friend is also having the same problem with ubuntu 7.04. can someone solve this weird problem?

[mediator]

Interesting! Can u give the output of "tracert 192.168.1.2" on windows and then "traceroute 192.168.1.2" and "traceroute 192.168.15.X" (i.e any system on that range) from Ubuntu!

Also what r u using for wireless network connectivity in Ubuntu?

[amitava82]

here is the traceroute information i got using 192.168.15.X ip, 255.255.255.0 subnet mask and 192.168.1.2 getway in my wifi card.

Windows

Tracing route to 192.168.1.2 over a maximum of 30 hops 1 4 ms 5 ms 11 ms 192.168.1.2 Trace complete.

Tracing route to 192.168.15.255 over a maximum of 30 hops 1 83 ms 32 ms 20 ms 192.168.15.15 Trace complete.


UBUNTU

trace route to 192.18.1.2 failed.
Traceroute to 192.168.15.26:
Hop Hostname IP Time1
1 amitava-laptop.local 192.168.15.123 0.225ms
1 no reply *
1 amitava-laptop.local 192.168.15.123 2004.159ms

I found this interesting output using route command in ubuntu

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.15.0 * 255.255.255.0 U 0 0 0 eth1

I see there is no gateway here but i did set gateway 192.168.1.2 in my eth1 i.e., wifi card. this could be the problem?

[mehulved]

try

sudo route add default gw <your gateway>

and then try again.

[amitava82]

i got the following error i try your command

SIOCADDRT: Network is unreachable

but if i try this code

route add 192.168.1.2 eth1

and ping 192.168.1.2 then i'm getting this output

From 192.168.15.123 icmp_seq=2 Destination Host Unreachable

So the problem is with the route table. now how to solve it?? I've attached windows route table if that helps

[mehulved]

Try adding eth1 to my command then.

 sudo route add default gw 192.168.1.2 eth1

[mediator]

@amitava : If ur using wireless on Ubuntu, then I suggest u use network-manager-gnome. U don't have to use static configuration then!

Since urs is wireless and can access 192.168.15.0 network also, then that network must also be having some ID (name). Try catching it.

U may use wifi-radar to detect the networks too.

Also the readings u posted for traceroute, why r there 2 entries of "amitava.local"? It looks to me as if it is going into a loop.

So I suggest u use network-manager-gnome first and then tell the story.

[amitava82]

I used gnome network manager for wireless. but as i told DHCP assigning ips 192.168.0.X class which are blocked for net access. only ips in 192.168.15.X are allowed for net. so its not the problem with network manager. i even tried with wifirader, knetworkmanager, wicd etc...

[freebird]

is this to do with subnet mask values?
post here the o/p of ifconfig

~$ifconfig

in ubuntu try in cli :

~$sudo  network-admin

and try to see what errs out?!


and finally do u have iptables firewall configure with some tools for eg: lokkit,firestarter etc?
if everything fails try for once:

~$sudo iptables  -F

and try

[amitava82]

YES YES!!! YES... I SOLVED THE PROBLEM. i wrote the command

route add 192.168.1.2 eth1

and my net fired up!!!!!!! Thanks everyone... time to update ubuntu and install some packages.

[mehulved]

Funny. You did that before too but that didn't work

[amitava82]

ya. i guess network was down that time. it happens often in my college..

[mediator]

INdeed very strange!

Tracing route to 192.168.1.2 over a maximum of 30 hops 1 4 ms 5 ms 11 ms 192.168.1.2 Trace complete.

Since 192.168.1.2 was the next hop, it shud have been automatically added in the routing table!