Mixing two uplinks with ipv6

[bigeasy]

I have two DSL links attached to my Linux router box. One Link is asymmetric and is used for mainly for downloads and the other is symmetric and is used mainly for uploads. Both links are from different IPs.
With IPv4 I've been using NAT and the router decided based on the port number which Link to use and the outside IP address matched the ISP. Now I'm puzzled how I can get this working with IPv6. The problem is that there is no NAT anymore. I don't want to give each client two ip addresses (one per ISP) and transfer the IP decision logic to each client.

Anyone an idea?

[jimb]

Get faster internet service (like cable or FiOS).

[efjeldstrom]

Would using the source route option header to insert a loose route work here?  You should be able to apply an ip6tables ROUTE target extension option for the port numbers that must be forced onto each interface without having to assign two addresses per host (assuming you don't want to go with asymmetric routing.)  I obviously haven't tried this, but I'm guessing that it would basically be a quick rewrite of your currently-existing NAT preforwarding rules.

Yes, I know that this is seen as an evil option header, but it seems to me that this is exactly the reason why the header was created in the first place.  Hopefully the upstream routers honour the header option!