Forum Debian Users Gang

root@worldshit:/home/mleko# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 46.36.37.40
netmask 255.255.255.0
gateway 46.36.37.1
#ipv6 static
iface eth0 inet6 static
pre-up modprobe ipv6
address  2a02:25b0:aaaa:200:0000:0000:0000:0002
netmask 64
gateway 2a02:25b0:aaaa:0000:0000:0000:0000:0001 




root@worldshit:/home/mleko#

root@worldshit:/home/mleko# ip -6 route show
2a02:25b0:aaaa:200::/64 dev eth0  proto kernel  metric 256 
fe80::/64 dev eth0  proto kernel  metric 256 
root@worldshit:/home/mleko#

root@worldshit:/home/mleko# ping6 www.cyberciti.biz
connect: Network is unreachable
root@worldshit:/home/mleko#

Now i can see, you got problem in v6 connectivity - these settings should resolve your problem. The main goal is to disable IPv6 autoconfiguration features in sysctl. 
 #/etc/network/interfaces
 allow-hotplug eth0
iface eth0 inet static
up ip -6 addr add 2a02:25b0:aaaa:200::1/48 dev eth0
 up ip -6 route add default via 2a02:25b0:aaaa::1

 
#/etc/sysctl.conf
net.ipv6.conf.default.autoconf = 0
net.ipv6.conf.default.accept_ra = 0
net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.all.accept_ra = 0
net.ipv6.conf.eth0.autoconf = 0
net.ipv6.conf.eth0.accept_ra = 0

root@worldshit:/home/mleko# cat /etc/sysctl.conf
#
# /etc/sysctl.conf - Configuration file for setting system variables
# See /etc/sysctl.d/ for additonal system variables
# See sysctl.conf (5) for information.
#

#kernel.domainname = example.com

# Uncomment the following to stop low-level messages on console
#kernel.printk = 3 4 1 3

##############################################################3
# Functions previously found in netbase
#

# Uncomment the next two lines to enable Spoof protection (reverse-path filter)
# Turn on Source Address Verification in all interfaces to
# prevent some spoofing attacks
#net.ipv4.conf.default.rp_filter=1
#net.ipv4.conf.all.rp_filter=1

# Uncomment the next line to enable TCP/IP SYN cookies
# See http://lwn.net/Articles/277146/
# Note: This may impact IPv6 TCP sessions too
#net.ipv4.tcp_syncookies=1

# Uncomment the next line to enable packet forwarding for IPv4
#net.ipv4.ip_forward=1

# Uncomment the next line to enable packet forwarding for IPv6
#  Enabling this option disables Stateless Address Autoconfiguration
#  based on Router Advertisements for this host
#net.ipv6.conf.all.forwarding=1


###################################################################
# Additional settings - these settings can improve the network
# security of the host and prevent against some network attacks
# including spoofing attacks and man in the middle attacks through
# redirection. Some network environments, however, require that these
# settings are disabled so review and enable them as needed.
#
# Do not accept ICMP redirects (prevent MITM attacks)
#net.ipv4.conf.all.accept_redirects = 0
#net.ipv6.conf.all.accept_redirects = 0
# _or_
# Accept ICMP redirects only for gateways listed in our default
# gateway list (enabled by default)
# net.ipv4.conf.all.secure_redirects = 1
#
# Do not send ICMP redirects (we are not a router)
#net.ipv4.conf.all.send_redirects = 0
#
# Do not accept IP source route packets (we are not a router)
#net.ipv4.conf.all.accept_source_route = 0
#net.ipv6.conf.all.accept_source_route = 0
#
# Log Martian Packets
#net.ipv4.conf.all.log_martians = 1
#

net.ipv6.conf.default.autoconf = 0
net.ipv6.conf.default.accept_ra = 0
net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.all.accept_ra = 0
net.ipv6.conf.eth0.autoconf = 0
net.ipv6.conf.eth0.accept_ra = 0
root@worldshit:/home/mleko#