IP4 address conservation method

[bjorn at mork.no (Bjørn Mork)]

William Herrin <bill at herrin.us> writes:
> On Wed, Jun 5, 2013 at 6:25 PM, Ricky Beam <jfbeam at gmail.com> wrote:
>> I won't argue against calling Linux "wrong".  However, the linux way of
>> dealing with ARP is well tuned for "host" and not "router" duty.
>
> I love Linux and use it throughout my work but I can't tell you the
> number of times its ARP behavior has bitten me. If you send a packet
> to a VIP on a Linux box and it doesn't have an arp entry for the
> default gateway, the Linux box will send an arp request... with the
> vip as the source. That is just wrong. Wrong, wrong, wrong. Use the
> damn interface IP when you arp for something on that interface. If the
> router doesn't happen to like the bad arp (since the VIP isn't on the
> router's LAN) the router will ignore it. And your service will merrily
> pop up and down depending on whether the Linux box has any traffic to
> originate.

Did you try setting sys.net.ipv4.conf.all.arp_announce=2 ?

Yes, the system default may be tuned for host/desktop usage, but it's
not like you *have* to use the system default.  Tweak it as you like.
And if there isn't enough knobs, then you can always add another one.
You have the source code.


Bj?rn