Strange network settings that blocks use of NAT

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jacortijo

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Joined
Dec 3, 2011
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4
Hi all,
I just arrived to my new apart hotel and I have a wired internet cable. it works perfectly when I connect it directly to my laptop.

surprisingly I connect my wifi router to the line and I cannot surf internet at all. I get a DNS error.

the IP is given by the hotel is quite weird (in the laptop)

Direc. inet:10.1.49.20 Difus.:10.1.49.20 Másc:255.255.255.255

the gateway is 10.1.48.1

the router is getting the same settings but I cannot access internet.
Configuration Type
Connection TypeAutomatic Configuration - DHCP
IP Address10.1.49.21
Subnet Mask255.255.255.255
Gateway10.1.48.1
DNS 1 8.8.8.8
DNS 2 8.8.4.4

I am getting a DNS error
Error 105 (net::ERR_NAME_NOT_RESOLVED): No se puede resolver la dirección DNS del servidor.

I dont really understand why the DNS is not resolved.. the router should forward the dns requests to the same DNS servers 8.8.8.8 but apparently it doesnt.

some could give me some ideas?

thanks in advance.
jose
 

TerryNet

Terry
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81,431
What OS on the laptop? What is "Difus."?

On the laptop do you get a browser redirect to force you to agree to be good before using the network?

Does the service latch onto the MAC Address of the first device that connected to it, and only allow that one? (Try cloning the MAC Address of the laptop's ethernet to the router to test this idea.)
 

jacortijo

Thread Starter
Joined
Dec 3, 2011
Messages
4
the OS is Ubuntu 11.10. Difus means broadcast , sorry that was Spanish word

there is not any website acting as proxy or so ever, it gets the ip and can access internet directly.
the router is a linksys WRT54G , I installed the dd-wrt firmware on it http://www.dd-wrt.com/site/index
I thought that it could be a bug in the original firmware but the issue persists...I went to the settings MAC Address Clone and set the laptop mac address but I keep getting the DNS error
Error 105 (net::ERR_NAME_NOT_RESOLVED):
/etc/resolv.conf only has the IP of the router 192.168.1.1
the WAN Ip for the router is
IP Address10.1.49.20
Subnet Mask255.255.255.255
Gateway10.1.48.1
DNS 1 8.8.8.8
DNS 2 8.8.4.4

so as far as I know the router should forward my DNS request to the DNS servers and answer to me but it doesnt.

I tried to add manually the two dns server to the resolv.conf but even a simple ping www.google.com doesnt go...

I am getting a bit paranoid, could be something related with the TTL? maybe it detects that the packets have two hops or more and it just discards the packets accordingly....

thanks mate.
jose
 

TerryNet

Terry
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Can you access the internet through the router (e.g., ping 8.8.8.8)? If so, you can define the DNS server address(es) on the computer or, I think, set the Linksys router to pass on the DNS server(s) it gets in its WAN (whoops, maybe not with the DD-WRT firmware).
 

Squashman

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19,786
That looks likes Googles DNS servers? Do you have those hardcoded in your router or on your PC?
 

TerryNet

Terry
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It looks as though they are assigned by the hotel's network.
 

jacortijo

Thread Starter
Joined
Dec 3, 2011
Messages
4
ok, I decided to come back to the original firmware from cisco... the latest 4.21.4 I also cloned the laptop MAC but
the still doenst work.
from my computer I can ping the 8.8.8.8 without any problem but from the router I cannot. I only get the following
PING 8.8.8.8 (8.8.8.8): 56 data bytes

that's all.... weird.

what it is struggling me is the settings is getting from the hotel DHCP server
10.1.49.20
255.255.255.255
gw 10.1.48.1

I tried to put this settings manually in the router and it simply doesnt let me do it. it says net mask illegal...
 

TerryNet

Terry
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In my mind I associate that mask with a PPP connection. For example, here is from an ipconfig /all (Windows XP) from a dial-up connection years ago:

PPP adapter PGHConnect:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : WAN (PPP/SLIP) Interface
Physical Address. . . . . . . . . : 00-53-45-00-00-00
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 4.159.104.168
Subnet Mask . . . . . . . . . . . : 255.255.255.255
Default Gateway . . . . . . . . . : 4.159.104.168
DNS Servers . . . . . . . . . . . : 64.136.173.4
64.136.164.76
NetBIOS over Tcpip. . . . . . . . : Disabled


However, I don't know what to look for in an ifconfig, nor why the computer would work but not the router.

If you can't get this working you can try using the router as just an ethernet switch and wireless access point. That should work for you if all you want is one computer using wireless, and it may work if you want to use multiple computers.

JohnWill's procedure (Aug. 30, 2008) for configuring a secondary router as a switch and, optionally, wireless access point follows.

Connecting two (or more) SOHO broadband routers together.

Note: The "primary" router can be an actual router, a software gateway like Microsoft Internet Connection Sharing, or a server connection that has the capability to supply more than one IP address using DHCP server capability. No changes are made to the primary "router" configuration.

Configure the IP address of the secondary router(s) to be in the same subnet as the primary router, but out of the range of the DHCP server in the primary router. For instance DHCP server addresses 192.168.0.2 through 192.168.0.100, I'd assign the secondary router 192.168.0.254 as it's IP address, 192.168.0.253 for another router, etc.

Note: Do this first, as you will have to reboot the computer to connect to the router again for the remaining changes.

Disable the DHCP server in the secondary router.

Setup the wireless section just the way you would if it was the primary router, channels, encryption, etc.

Connect from the primary router's LAN port to one of the LAN ports on the secondary router. If there is no uplink port and neither of the routers have auto-sensing ports, use a cross-over cable. [You will not need a cross-over cable if one of the "routers" is a computer.] Leave the WAN port unconnected!

This procedure bypasses the routing function (NAT layer) and configures the router as a switch (or wireless access point for wireless routers).

For reference, here's a link to a Typical example config using a Netgear router
 
Joined
Dec 7, 2011
Messages
1
Ive had a similar problem at a hotel i stayed in recently, my laptop would connect to the router on ip 172.28.64.1 / 255.255.255.255 , but as i have several network ports, wireless and 2 virtual wireless and also a wired then how can my laptop reply to packets as it does not know which oneto send them through. I disabled all my network interfaces except the one i was using and it works fine. Seems like a easy way for the hotel to stop people from maybe seeing eachother on the network but causes many guests headaches who are not technically aware.
 

jacortijo

Thread Starter
Joined
Dec 3, 2011
Messages
4
Eureka!! it work, I disable dhcp in the router and connect the cable from the hotel to the switch. now I can go internet from the laptop using the wireless... no access from mobile phone or other laptop. I guess it is limited to one ip... :/

i am getting pretty mad with this so I decided to try to share the internet in the laptop over bluetooth... I was googling a bit and I found a software called blueman in linux that it does the trick. I installed but I am having new issues with the settings.

it says that there is not a dhcp running in my computer. So I tried to run a dhcp server on the bluetooth device

[email protected]:/etc/network# dhcpd hci0
Internet Systems Consortium DHCP Server 4.1.1-P1
Copyright 2004-2010 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Wrote 0 leases to leases file.

No subnet declaration for hci0 (no IPv4 addresses).
** Ignoring requests on hci0. If this is not what
you want, please write a subnet declaration
in your dhcpd.conf file for the network segment
to which interface hci0 is attached. **


Not configured to listen on any interfaces!

Here is where i get quite lost... I dont know how to set up a DHCP server on my bluetooth device. I even doubt whether that is possible or not...
I tried to modify the file /etc/network/interfaces acding the new interface with the ip address

iface hci0 inet static
address 10.0.0.1
netmask 255.255.255.0
network 10.0.0.0
broadcast 10.0.0.255
gateway 10.0.0.1
and I also added the network to the /etc/dhcp/dhcp.conf


subnet 10.0.0.0 netmask 255.255.255.0 {
option routers 10.0.0.1;
option subnet-mask 255.255.255.0;
pool {
range 10.0.0.10 10.0.0.20;
}
}
but still when I try the command dhcp hci0 I get the same error as before...

someone has done this before? set up a dhcp server over bluetooth?

thanks once again
jose
 
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