Weird thing is that zeroshell.net forum that doesn’t support coockies still is confused and asks for user-pass each time I refresh a page. Looks like we cannot avoid the static route…
I think the issue is routing persistence across multiple TCP sessions. The fixes I put in only keep a TCP session going to the correct interface. The next TCP session will do a fresh pick of the WAN interface to use.
Since each page refresh on a web site is a new TCP session there is a good possibility, depending on your load balancing metric, that the new session will be on a different interface.
In my case that hasn’t been a problem as I have a 100:1 ratio in speed between my two ISP and the slow one has enough traffic from incoming mail and VoIP that pretty much everything internally generated gets routed on the high speed ISP.
I haven’t yet looked into how one can make route persistence work across multiple TCP connections. This will be needed not just for this site to make cookies work but for any HTTPS site.