[BL] BL as wireless gateway

sindi keesan keesan at SDF.ORG
Mon Oct 3 11:52:43 EDT 2011


Steven, please could you find the time to help with this?
Christof had it working a few years ago with your help ('gateway between 
two laptops' thread.

AT&T wants to double my internet rates after the first year and the 
neighbor is happy to share his wireless signal with me instead.  I can 
pick it up at my front window and want to use a laptop with BL2 (or BL3) 
to redistribute the signal to other computers via a hub.

I am testing on another setup, with two laptops plugged into a hub that is 
connected to a wired router (192.168.2.1).  I also plugged my Apple 
wireless router into the hub (which lets me go online wirelessly - I 
have probably turned off DHCP on it so it will work plugged into another 
router via a series of two hubs).  I want to go online wirelessly with one 
of the computers and share the signal to the other via the wired hub.

A.  BL2 with wired (eth1) and wireless (eth0) pcmcia cards.  It connected 
properly via eth0 to wireless network 10.0.1.1 router with IP number 
10.0.1.2 for BL.  I set IP address and default gw manually and DNS 
nameserver 192.168.0.1 (DSL modem) in /etc/resolve.conf

For the wired network I chose different IP numbers from my other equipment 
(wired router 192.168.2.1, DSL modem 192.168.0.1)

ifconfig eth1 192.168.3.1  (1.1 would also have worked here)
(gateway)

B.  Puppy Linux with onboard wired eth0 (does not usually work with Puppy 
though it always does with BL2) and USB wired eth1.  With ethernet modules 
loaded it will connect directly to internet using the wired router as 
default gw so I know the hardware works.  Then I set it manually to use 
the BL2 laptop as gateway instead.

(I also tried BL2 the same way with onboard wired ethernet as eth0 
instead of eth1).

ifconfig eth1 192.168.3.2
(client)
route add default gw 192.168.3.1   (use other laptop as gateway)

These two computers will now ping each other (via the hub).

I then set the first one to forward to the second one
echo "1" > /proc/sys/net/ipv4/ip_forward
(that file does now read 1)

The client computer will not access the internet  - what did I do wrong?
It will only ping the gateway computer, not 8.8.8.8 or a URL.

I also tried to set up a firewall on the gateway (BL2)
ipchains -P forward DENY
ipchains -A forward -s 192.168.3.100/24 -j MASQ

'Protocol not available'
(I am using a small laptop kernel without ipchains support - would
this affect anything else above?).

Do I need ipchains support to do port forwarding?  Should I try a larger 
kernel or BL3 big kernel on the gateway computer?

I could use even a 133MHz laptop with 24MB RAM (too little RAM for Puppy 
Linux) as the wireless gateway with BL, and a non-cardbus orinoco card 
that does WEP.  The slower laptops use less electricity.  I should be able 
to set even Mac and Windows computers to an IP address manually (though I 
don't know how to set default gw in Windows yet).

Sindi


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