On Thu, 2009-10-22 at 11:03 -0400, Kevin Loch wrote:
If, on the other hand, the REAL desire is to have a DHCP server break the tie in the selection between several routers that advertise their presence, that wouldn't be unreasonable.
In some configurations not all hosts are supposed to use the same router. We need the _option_ to specify a default gateway and have the override any RA's a host may see.
It would be a tool, and if someone wants to use a tool, they can. It won't be my thumb they hit :-) But I can't see how a DHCP server can know enough about the routers to be able to send out useful discrimination information. So it will have to be manually entered, or come from an IPAM, or... Nor can I see how the DHCP server can identify the routers to the host except by their addresses, and these can change or be removed without the DHCP server finding out. The only way I can see it working is if the host were smart enough to compare the DHCP router discrimination info with the information it has received via RA and delete mismatches, or possibly just revert to using RA information if any mismatches at all are detected. That would be an item the DHCP server could specify as well - what to do in case of a mismatch. It could even be specified on a per-router basis, though the whole thing seems to be getting a bit unwieldy now. The DHCP servers will not be on the same subnets as all the routers involved, so they can't sniff the RAs themselves - unless we set up an RA relay... hmm. I don't see DHCP-delivered router preferences as being something that will "break the Internet". In the vast majority of cases they will be unnecessary. For those that do need it though, and if it can be done, why not? Regards, K. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Karl Auer (kauer@biplane.com.au) +61-2-64957160 (h) http://www.biplane.com.au/~kauer/ +61-428-957160 (mob) GPG fingerprint: 07F3 1DF9 9D45 8BCD 7DD5 00CE 4A44 6A03 F43A 7DEF