Yep the old rp_filter trap!

Had me stumped for about 10 mins as well.

You only need to disable it on the sm200d interface though.

On Tue, 23 Apr 2002 [EMAIL PROTECTED] wrote:

> Hello ramon,
>
> due to spoof prevention... have a look in you boot scripts for rp_filter
>
> and change...
>
> for f in /proc/sys/net/ipv4/conf/*/rp_filter; do
>     echo 1 > $f
> done
>
> to
>
> for f in /proc/sys/net/ipv4/conf/*/rp_filter; do
>     echo 0 > $f
> done
>
> --
> Best regards,
>  evilbunny                            mailto:[EMAIL PROTECTED]
>
> Tuesday, April 23, 2002, 11:47:36 AM, you wrote:
>
> rb> Hi peoples,
>
> rb> I've got a tricky one which has got me a little stumped..
>
> rb> I'm installing satellite for my net connection. Ive got it all working
> rb> The ISP is a reseller of the iHUG service.
>
> rb> The Dial up account is with a local ISP. (not an iHug specific account)
> rb> Ive got the card all configured (ie the driver loads etc)
> rb> and the Dialup appears to allow me to change my source IP outgoing.
>
> rb> How does it the satellite stuff work:
> rb>         data goes out via the ppp0:0 (dialup) interface
> rb>         with a source address of the Satellite card
>
> rb>         The satellite card is configured with a dummy IP address
> rb>         and it receives packets (from my ISP) sent to the external IP Address.
> rb>         (there is an app running in bg that 'locks' on to the satellite and get 
>the
> rb> data)
>
> rb> How is it setup:?
> rb>         (say the satellite External IP address is 1.2.3.4 ie real.
> rb>         the card drivers are loaded
> rb>         The module is loaded into the kernel and then the app is loaded.
> rb>         The the 'NIC' side of the card is configured.
> rb>         # ifconfig sm200d 10.0.0.1
>
> rb>         Dialup the ISP via modem (local IP given 5.5.5.1, remote ip given
> rb> 5.5.5.254)
> rb>         # ifconfig ppp0:0 1.2.3.4 netmask 255.255.255.255 pointopoint 5.5.5.254
>
> rb>         delet the old ppp0 route
> rb>         # route del default
>
> rb>         add new route (via ppp0:0 so it sets the source of the IP to the sat IP)
> rb>         # route add default gw 5.5.5.254 dev ppp0:0
>
> rb> What happens ?
> rb>         I can ping an external host
> rb>         # ping www.ibm.com
>
> rb>         The return ping response actually DO come back on the sm200d interface
>
> rb>       sm200d    Link encap:Ethernet  HWaddr 00:xx:xx:xx:xx:xx
> rb>           inet addr:10.0.0.1  Bcast:10.255.255.255  Mask:255.0.0.0
> rb>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> rb>    ---->  RX packets:97 errors:0 dropped:0 overruns:0 frame:0
> rb>           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> rb>           collisions:0 txqueuelen:100
> rb>           Interrupt:9
>
> rb>         The box I am doing this on is a firewall (smoothwall) but I have dropped
> rb> all the
> rb>         ipchains ruls and set default policies for input,output as ACCEPT and
> rb>         forward as MASQ (because there is an internal network attached to eth0 @
> rb> 192.168.1.0
>
> rb>         And I also set some ipchains logging with ipchains -A input -d 1.2.3.4 -l
> rb>         and I can see all the reponses come back ..
>
> rb> my question?
> rb>         How do I get the card/linux to deliver them to the application (eg ping) 
>or
> rb> whatever
> rb>         given that they come back on a different interface to what sent out on?
>
> rb>         How can I debug this further to see where/why they are going no where?
>
> rb>         How is this 'jump' between NIC's configured ?
>
>
>
> rb> Any suggestions are MUCHly appreciated! :^)
>
> rb> - ramon.
>
>
>
>
>
>
> rb> This email was sent to you by Ramon Buckland, Software Engineer at f5.
> rb> You can reach Ramon directly on 0421 379 694.
>
> --
> SLUG - Sydney Linux User's Group - http://slug.org.au/
> More Info: http://lists.slug.org.au/listinfo/slug
>

-- 
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