Openvpn connect over IPv6 on Android

Mr__Mo · Post by **Mr__Mo** » Sat Oct 05, 2013 10:31 am

I am trying to setup openvpn over IPv6 using an android 4.0.3 tablet with an up-to-date "OpenVPN Connect" as client. The client is connected to another android which provides the IPv4 internet via a mobile hotspot. The client also obtains its IPv6 address from a tunnelbroker. I can successfully ping6 the VPN server from the tablet and vice versa. However, it is not possible to establish a vpn connection as openvpn fails with the following error:

Code: Select all

P:OpenVPN 2.3.2+dspatch4 android-14-armeabi-v7a [SSL (OpenSSL)] [LZO] [SNAPPY] [EPOLL] [MH] [IPv6] built on Sep 12 2013
P:MANAGEMENT: Connected to management server at /data/data/de.blinkt.openvpn/cache/mgmtsocket
P:MANAGEMENT: CMD 'hold release'
P:Control Channel Authentication: tls-auth using INLINE static key file
P:Outgoing Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication
P:Incoming Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication
P:LZO compression initializing
P:Control Channel MTU parms [ L:1558 D:166 EF:66 EB:0 ET:0 EL:0 ]
P:Socket Buffers: R=[163840->131072] S=[163840->131072]
P:Data Channel MTU parms [ L:1558 D:1450 EF:58 EB:395 ET:0 EL:0 ]
P:Local Options String: 'V4,dev-type tun,link-mtu 1558,tun-mtu 1500,proto UDPv4,comp-lzo,cipher AES-128-CBC,auth SHA1,keysize 128,tls-auth,key-method 2,tls-client'
P:Expected Remote Options String: 'V4,dev-type tun,link-mtu 1558,tun-mtu 1500,proto UDPv4,comp-lzo,cipher AES-128-CBC,auth SHA1,keysize 128,tls-auth,key-method 2,tls-server'
P:Local Options hash (VER=V4): '9fde0044'
P:Expected Remote Options hash (VER=V4): '2f29e19c'
P:Protecting socket fd 4
P:MANAGEMENT: CMD 'bytecount 2'
P:MANAGEMENT: CMD 'state on'
P:MANAGEMENT: CMD 'needok 'PROTECTFD' ok'
P:UDPv6 link local (bound): [AF_INET6][undef]:1194
P:UDPv6 link remote: [AF_INET6]2001:_redacted_::1:1194
P:MANAGEMENT: >STATE:1380896313,WAIT,,,
P:Wwrite UDPv6 []: Network is unreachable (code=101)
P:Wwrite UDPv6 []: Network is unreachable (code=101)
P:Wwrite UDPv6 []: Network is unreachable (code=101)
P:Wwrite UDPv6 []: Network is unreachable (code=101)
P:Wwrite UDPv6 []: Network is unreachable (code=101)
P:TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
P:TLS Error: TLS handshake failed
P:TCP/UDP: Closing socket

Client config:

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client
dev tun0
tun-ipv6
proto udp6
remote 2001:_redacted_ 1194
resolv-retry infinite
nobind
persist-key
persist-tun
comp-lzo
cipher AES-128-CBC
ns-cert-type server
verb 3
<ca>...</ca>
<cert>...</cert>
<key>...</key>
<tls-auth>...</tls-auth>

However, the same config works like a charm if i connect from a linux netbook instead of the tablet (with the only difference being that in this setup there is no intermediate mobile hotspot). Seeing as ICMP works just fine I doubt it's an IPv6 routing problem.

Has anyone already come across this problem or has any idea as to what is going wrong here?

Regards
MM