Date: Thu, 10 Nov 2005 13:39:07 +0000 From: Brian Candler <B.Candler@pobox.com> To: Jon Otterholm <jon.otterholm@ide.resurscentrum.se> Cc: freebsd-net@freebsd.org Subject: Re: arp-proxy Message-ID: <20051110133907.GA67265@uk.tiscali.com> In-Reply-To: <1131629107.878.22.camel@localhost.localdomain> References: <1131541588.996.13.camel@localhost.localdomain> <20051110124903.GB67086@uk.tiscali.com> <1131629107.878.22.camel@localhost.localdomain>
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On Thu, Nov 10, 2005 at 02:25:07PM +0100, Jon Otterholm wrote: > In all this - our role is similar to an ISP, but we are buying access to > our customers from an external part. Every customer is delivered on a > separate vlan trunked. > > - Our DSL customers cannot be set on the same VLAN i a single DSLAM > (don't ask me why - ask Alcatel). > - We cannot build a simple bridge because the Network service provider > can't handle when a MAC-address shows up on 2 different VLAN's. > > The arp-proxy should do the following: > - Forward any broadcast packets but rewrite src to its own mac. > - Forward unicast packets according to FDB but rewrite src to its own > mac. Can you not perform normal routing - that is, allocate a separate IP subnet to each VLAN? This uses some more IPs than a 'flat' addressing space, but it's guaranteed to work properly. If your DSL traffic is presented as PPPoE, maybe you can get away with just having a separate PPPoE listener on each VLAN. If it's presented as L2TP you could use private IPs for the tunnel endpoints. Otherwise, a bridge which rewrites source MAC addresses as packets pass through - that's just too awful to contemplate. As you say, you'd also have modify ARP responses to have the bogus MAC addresses too. Dealing with multicast, IGMP, Netbios... no I really don't want to contemplate it :-) Regards, Brian.
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