[pptp-server] proxy-arp with PPTP

Eric Stratte estradey at pullman.com
Mon Nov 8 22:51:00 CST 1999

I think I might have answered my own question below, but it makes me wonder
what the difference between ARP routing rules and IPCHAINS is?

I had proxy_arp set to 1 for pppx, but the local eth0 that I am trying to
route over had its proxy_arp set to 0.  If I want to have the pppx and eth1
all appear on the same subnet and talk to each other, do I need proxy_arp
set to 1 for eth1?  Will this handle the broadcast packets, since the below
firewall rules don't seem to.(I added a forward rule for to

None of my gaming buddies are around to try this at the moment so I thought
I'd throw it up here.  If this is true, it might make a good FAQ topic,
although perhaps more appropriate for PPP.


Eric Stratte wrote:

> I've gotten it to work mostly, with lots of help from tmk -- Thanks!
> I think ARP may be broken on my setup.  I still get NOARP on the ppp0
> ifconfig.
> I have the arp --set ...etc. in ip-up.local and I have done echo
> 1>/proc/net.../proxy_arp
> But,  I have setup the folowing IPCHAINS rules that correctly forward
> packets
> :input ACCEPT
> :forward DENY
> :output ACCEPT
> ipchains -A forward -s  -i eth0 -j ACCEPT forward any ppp
> subnet traffic to the local nic/net
> ipchains -A forward  -d ! -i eth1 -j MASQ handle outbound
> internet traffic
> ipchains -A forward  -d -i ppp0 -j ACCEPT send stuff out
> to the ppp interfaces
>  .
> .
> last line repeated for ppp1, ppp2, etc.
> Now this allows everyone to appear on the subnet, but
> broadcast packets don't seem to make it all the way through...to all
> ends...?
> do I need another ipchains line for the broadcast address forward to
> pppx?(i.e x.x.x.255)

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