Bug#861115: Please consider increasing net.ipv6.route.max_size default value

[Tim Bray <tim@provu.co.uk>]

I also agree.

I've just spent a month tracking down an issue where IPv6 networking 
connections hang.  Using Debian buster, 4.19.0-6-amd64.

Machine carries a full IPv6 table, received via BGP. About 80k routes.

Symptoms were BFD dropping out.  Connectivity hangs.

setting net.ipv6.route.max_size to 2147483647 fixed all issues.    
(aware this might be too big)

Later kernels  (5.4.11) cause a dmesg when full.

Tim