I guess you can't do this, since a believe there is a single linux arp table. It is not per-interface.
If you had hosts with unique IPs on both nets, that would be another story: you could use some sort of VPN or Bridge functionality. You could also be able to avoid packets passing through the bridged/VPNed interfaces thanks to iptables.
Cheers,
Giampaolo
> -----Messaggio originale-----
> Da: [email protected]
> [mailto:[email protected]]Per conto di Innocenti
> Maresin
> Inviato: sabato 12 agosto 2006 17.09
> A: LKML
> Oggetto: Q: remapping IP addresses for inbound and outbound traffic
>
>
> Hello!
>
> Let one Linux box have two interfaces to IPv4 networks,
> and for some IP both networks have the host with this IP address,
> e.g. from RFC1918.
> Or even both use the same IPv4 address block.
> We can say that one IP from the first network
> and numerically the same IP from the second "means" different hosts.
>
> The software of this box needs to connect all hosts in both networks,
> and also to receive inbound TCP connections.
> The evident way is to "remap" overlapping IPv4 area of one network
> to some "place" not used neither in it nor in other.
> This means that, when we receive a packet from remapped area,
> the kernel should replace the source IP to an "internal representaion".
> Versa, sending something to "internally represented" IP
> the kernel should replace such IP by its external value.
> I clarify these terms so carefully because in
> news:comp.os.linux.networking
> some people state that I "use terms in strange ways" :)
>
> The question is: how to do it?
> Please, don't say quicky "iproute2" and "RTFM".
> Iproute2 can do such things when *forwarding* packets.
> I need no forwarding at all, no *connection* between 2 networks.
> I need only to *serve* both networks,
> such that some "external" IPs need to be replaced by internally
> used IP and versa.
> All this at one Linux box.
> No forwarding traffic. Only inbound and outbound.
>
> So, suppose that I try to use FastNAT/iproute2 on Linux 2.4,
> a "dummy NAT address" is an "internally represented" in my terms,
> and "via" address (in iproute2 terms) is my "external".
> Then, by iproute2 idiots' design, I can't locally send packet
> to so named "dummy NAT address".
> I even can't use connect() on it, the kernel says "Invalid argument".
> So, I really can't use my "internal addresses".
>
> Ipfilter also cannot solve this problem.
> There is no means to translate inbound packets' source address
> (there is no INPUT chain in -t nat and PREROUTING can't do SNAT),
> but services need to see packets as coming from internally
> represented IP.
>
>
> There is some more or less trivial ideas:
>
> * Use IPv6 (IMHO it's possible, but I seek yet for simpler solution);
>
> * Use extra hardware - I am not willing to do so for many reasons;
>
> * Read docs more carefully ;) - I read relevant ip-cref sections,
> but FastNAT feature is poorly documented in this Kuznetsov's paper,
> many anothers docs cite Kuznetsov and generally give even less details;
>
> * Modify the kernel sources - Of course, I will,
> but it's not evident for me that the trouble caused by some few errors,
> I'm not sure that kernel may use a "dummy NAT address"
> as destination of locally generated packets without major changes.
>
>
> Maybe, somebody knows about "non-official" kernel patches?
>
> P.S. please send me Cc when replying to this message.
>
>
> --
>
> qq~~~~\
> / /\ \
> \ /_/ /
> \____/
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
