EDIT: it became quite obvious to me that my problem is about the same as described in Debian bugreport #657109
Wireless driver zd1211rw, running LMDE UP4 (MATE interface). And yes, IPv6-capable ISP and IPv6 enabled in router.
Previously, it worked fine. But since I formatted and installed new from the 201204 RC ISO, there's trouble
Available for all users
IPv4: DHCP; IPv4 required;
IPv6: manual; 2a01:e35:XXX:d6a0::20; 64; 2a01:e35:XXX:d6a0::
All right, maybe I miss something...
ipv6.proof.ovh.net has IPv6 address 2001:41d0:2:876a::1
connect: Network is unreachable
And test-ipv6.com only reports "No IPv6 address detected" (no test related to IPv6 passes, even the one without DNS)
And yes, IPv6 is enabled in ufw and in the Firefox config too.
Setting Network-Manager method to "ignore" makes it give the MAC-related IPv6 for a few seconds (doesn't work anyway), and "automatic" makes constantly the network trying to connect without success. According to my backups, network-manager has to be like stated above. I think I definitively miss something... What kind of checks can be done ?