[slightly OT & long] PPPoE iptables NAT
Norberto Quintanar
nquintanar at yahoo.com
Fri May 6 08:17:29 MDT 2005
Joseph,
I couldn't agree with you more. I used to believe that I had to save
all old hardware from landfills. I set up an old PC250Mhz with
smoothwall - http://www.smoothwall.org/ - as a gateway firewall. It
worked great. Then winter came and my electricity bill was getting
out of hand. Without going into extreme detail, computers use a lot
of electricity compared to a DSL modem and a router/ firewall with
NAT.
Just my $0.02
> Albrecht,
>
> My experiences with using a computer as a gateway to the Internet
> for a
> home network have taught me that it can be done, but why would you
> want
> to. It's not very efficient, and is a waste of a compute resource.
>
> The simplest solution is use a router that performs NAT as your
> gateway:
>
> ISP
> --------
> |
> |
> DSL Modem
> ---------
> |
> |
> Router [with builtin NAT &
> firewall]
> --------
> |
> |
> Switch [for additional ports]
> --------
> |...|
> |...|
> local machines
>
>
> I am using a LinkSys BEFSX41:
> * performs NAT
> * builtin firewall
> * supports 2 VPN's
> * acts as a 4 port switch
>
> I need more than four switch ports so I have added an additional
> LinkSys
> 8 port switch [EG0801W].
>
> The router is "dual-homed", meaning that it has two IP addresses:
> * a DHCP address assigned by the ISP
> * local network IP address, 192.168.0.254 [assigned by me]
>
> All local machines set 192.168.0.254 as the gateway.
>
> For example,
>
> % netstat -rn
> Kernel IP routing table
> Destination Gateway Genmask Flags MSS Window
> irtt Iface
> 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0
> 0 eth0
> 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0
> 0 lo
> 0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0
> 0 eth0
>
> The gateway router / NAT solution works well and requires little
> maintenance once configured.
>
> -Joseph
>
>
==============================================================================================
> On Fri, 2005-05-06 at 11:47 +0000, Albrecht Dreß wrote:
> > Hi,
> >
> > sorry for a slightly off-topic question regarding NAT with a
> PPPoE network.
> >
> > I have a home network looking as follows:
> >
> > 192.168.42.3
> > ----------- -------
> > | G4 Silver | | |---DSL Modem (ppp0)
> > ISDN---|ippp0 eth0|---|Switch |---more Macs (192.168.42.x)
> > ----------- -------
> >
> > The G4 is running Yellowdog 4.01 with a self-compiled 2.6.11.4
> kernel.
> >
> > The "old" setup was an ISDN connection (no DSL present), and the
> G4 worked
> > as router. Everything was perfect for the "local" net, except
> that the
> > hardware (AVM Fritz) was not supported by MacOS, so I had no
> internet on
> > the G4 (and connected clients) when running OS X.
> >
> > Therefore, I removed the ISDN card, got DSL, plugged the modem
> into the
> > switch, and now everything works fine with OS X. After a little
> fiddling
> > around with ipfw and natd, I have routing support with OS X
> client.
> >
> > Now I tried Linux, and I have internet on the G4 itself, but
> packets from
> > the local net are apparently not routed/forwarded correctly. I
> did not
> > change the NAT rules in iptables (except replacing ippp0 by ppp0,
> of
> > course):
> >
> > <snip>
> > [root at antares root]# iptables -t nat -L -n
> > Chain PREROUTING (policy ACCEPT)
> > target prot opt source destination
> >
> > Chain POSTROUTING (policy ACCEPT)
> > target prot opt source destination
> > MASQUERADE all -- 192.168.42.0/24 0.0.0.0/0
> >
> > Chain OUTPUT (policy ACCEPT)
> > target prot opt source destination
> > </snip>
> >
> > Running tcpdump on both eth0 and ppp0, I can see that e.g. a http
> (tcp/80)
> > request from the local net is going through eth0, and the same
> packet is
> > then passed via ppp0. The response, though, is *not* returned to
> the
> > requesting client.
> >
> > I am using the kernel-based pppoe modules (pppoe, pppox), not the
> roaring
> > penguin package coming with YDL. Does anyone have an idea why
> forwarding
> > doesn't work with this setup? Any hints how I should configure my
> box? Or
> > is it impossible to use the dsl modem and the local net at the
> same
> > Ethernet interface (but why does it work with OS X, then)? Any
> pointers?
> >
> > HELP! I'm really lost here...
> >
> > Thanks in advance for any help,
> >
> > Cheers, Albrecht.
> >
> > _______________________________________________
> > yellowdog-general mailing list
> > yellowdog-general at lists.terrasoftsolutions.com
> >
>
http://lists.terrasoftsolutions.com/mailman/listinfo/yellowdog-general
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> site:terrasoftsolutions.com'
> --
> joseph_sacco [at] comcast [dot] net
>
> _______________________________________________
> yellowdog-general mailing list
> yellowdog-general at lists.terrasoftsolutions.com
>
http://lists.terrasoftsolutions.com/mailman/listinfo/yellowdog-general
> HINT: to Google archives, try '<keywords>
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