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On Sat, 27 Nov 1999, Julian Anastasov wrote:
> > I haven't looked real hard for these arp requests with tcpdump
> > as the VIP was on wierd devices that I didn't think tcpdump
> > listened too (eg tunl0 or lo:0). I will go look.
>
> You have to tcpdump -i eth0
>
OK
> >
> > > > The realserver has a packet src=VIP,dest=ClientIP but
> > > > when it asks for a route to ClientIP it does so from
> > > > the realserverIP (I thought). The LVS works fine for
> > > > me if there is no route for the VIP on the realservers.
> > >
> > > No. It works because there are no other hosts to ask "who-has VIP
> > > tell HOST".
> >
> > Why does a realserver what to know who has the VIP? Doesn't
> > each realserver think it has the VIP and not need to ask
> > (I don't see any arp table entries for the VIP on the
> > realservers).
>
> The other hosts (if any) can ask about VIP but the real servers
> ask about their default gateway (LVS, director).
yes got this
> > > But the real servers always ask "who-has LVS tell VIP" and may
> > > be reply is not send from LVS as the VIP is configured in LVS too.
> >
> > I take it that what you are calling the LVS, I am calling the director (I
> > call the LVS=director+realservers). In this case are you saying that the
> > realservers are asking for MAC address of the director? Why are
> > they doing that?
>
> It's their default gateway.
ah, I don't usually use the director as the default gw for realservers in
VS-Tun and VS-DR, and when I do I use the regular IP on the director
(DIP) rather than the VIP.
> > > Sorry, I'm always talking about the more complex configuration
> > > where any number of the real servers can work as LVS when the host LVS is
> > > down. But the above configuration works, i.e. one LVS box and no other
> > > hosts on the LAN which can ask "who-has VIP tell HOST".
> > >
> >
> > Are you saying that there is one director box and no other realservers
> > on the LVS local LAN which can ask "who-has VIP tell realserver"?
>
> I mean if the director and the real servers are the only hosts and
> noone talks with them => there is no ARP problem.
:-)
> The router and the
> director are connected on LAN1 and only the director replies to the
> router.
fine, HOST here is the router
> > What's going to happen to all of this with the 2.4.x kernels? Are we going
> > to have to start all over again like we did with the 2.2.x kernels? Is
> > netfilter (which I know almost nothing about) going to change the arp
> > problem?
>
> These patches have to be modified for 2.4. Netfilter can't solve
> this problem. Its job is connection tracking, packet mangling and
> firewalling. It can only deny ARP queries from the router to the director
OK
> but it can't handle the ARP queries "who-has ROUTER/DIRECTOR tell VIP" and
> to rewrite them to "who-has ROUTER/DIRECTOR tell WEB1". It's job for the
> ARP code.
OK thanks
Joe
--
Joseph Mack mack@xxxxxxxxxxx
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