[TriLUG] Sharing WiFi through Ethernet

[Brian McCullough]

On Fri, Aug 15, 2014 at 01:22:39PM -0700, Joseph Mack NA3T wrote:
> On Fri, 15 Aug 2014, Brian McCullough wrote:
> 
> >Unfortunately, changing the netmask had no effect on the end result.
> 
> just going through basics here. There's got to be something silly going on.

I agree.  Everything LOOKS reasonable, but packets aren't going through.


> does the output of
> 
> iptables -L -t -n nat
> 
> look sensible eg
> 
> Chain POSTROUTING (policy ACCEPT)
> target     prot opt source               destination
> MASQUERADE  all  --  192.168.1.0/24       0.0.0.0/0

Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination         
MASQUERADE  all  --  10.0.0.0/24          0.0.0.0/0           


> it the FORWARD chain all ACCEPT?
> 
> iptables -L -n

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination    



> are you nat'ing the correct device?

Probably.

The environment:

Laptop
wlan0: 192.168.1.x -- talks to the outside world.
eth0:  10.0.0.x -- talks to the subnet ( the target device )
Has above iptables.  Has ip_forward set to 1. Has dnsmasq configured to
talk only to eth0.
DNSMasq: serves addresses to eth0 subnet. Gives DNS addresses 8.8.4.4,
8.8.8.8. Shows eth0 address as gateway.


Second device:
on 10.0.0.0/24 network
usually given 10.0.0.101 address
Recognizes that it has IP address.
Recognizes "local network"
Fails to communicate with Internet.

DNSMasq log on laptop shows DNS activity which seems reasonable for
second device. ( appropriate addresses searched and returned )


What else can I say?



> Joe

Brian