Link to home
Start Free TrialLog in
Avatar of ginaa
ginaa

asked on

linux as route

Dear all,
I use red hat 7.3 as private ISP.
situation as follow
  1. linux+ADSL pppoe connect internet OK (eth0, ppp0)
  2. linux com port + MODEM
  3. win98 client dial-up connect OK (ppp1, use private ip 10.10.10.X)
  4. after dial-in, linux route has a row for 10.10.10.x
  5. linux ip-forward enabled
  6. setting no firewall
  7. client connect linux OK, but internet fail.

Anything else?
regards
ginaa
Avatar of ahoffmann
ahoffmann
Flag of Germany image

> .. but internet fail.
what do you mean by that?
Avatar of ginaa
ginaa

ASKER

I mean my win98 client can not connect internet through my linux.

regards
ginaa
You want IP Masquerading, also known as Network Address Translation, or NAT.  The functionality is available through any of the three firewall tools.

The quickest method, using IPCHAINS as root:

# modprobe ipchains
# ipchains -A FORWARD -s 10.0.0.0/255.0.0.0 -j MASQ

The single ipchains line above will forward your entire 10.x.x.x subnet through the linux box to the internet.  You will also need your DSL to be the default route on the linux box (very important).  This makes it easy to set up a "home" or "trusted" network using DHCP grants for the same subnet, so to get internet access, it's literally "plug-n-play" with the network jack.  Note that ipchains has some limitations that cause FTP to not work, but there are some modules you can probe for that work around these issues.

It's a little more involved for iptables, but the stateless inspection makes life so much easier...and is nearly rid of any of the issues of ipchains.
Avatar of ginaa

ASKER

follow you instructions
I got a message:
>> ipchains: protocol not available
What's the problem?
I already check the item of ipchains in setup/service screen

regards
ginaa
sounds like you have iptables, try this:

  iptables -t nat -A POSTROUTING -o wan-nic -j MASQUERADE

(where you replace wan-nic bythe interface name connected to your ADSL router)
Avatar of ginaa

ASKER

Thanks for response
After execute "iptables -t nat -A POSTROUTING -o wan-nic -j MASQUERADE", it works.
But then I reboot linux box, I can not dial in anymore.
I got a error msg:
   LCP: timeout sending Config-Requests
What's up?
I have two lines in file "pap-secrets", one for linux box ADSL dial-out, the other for client dial-in linux box.
file "options.ttyS1" as follow
 auth
 +pap
 persist
 passive
 ktune
 10.10.11.1:10.10.11.3
Any suggestion?

regards
ginaa
ASKER CERTIFIED SOLUTION
Avatar of ahoffmann
ahoffmann
Flag of Germany image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of ginaa

ASKER

thanks, ahoffmann
your iptables command solve my question here.
so i will accept as answer.
can not dial-in linux box after reboot may be another problem.
or simultaneously dial-in and dial-out should have special setting.
maybe i need to create another question.

regards
ginaa

Thank. You're welcome.