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Jacob Evans
Asked: 2017-02-12 18:07:34 +0800 CST

Unable to communicate over vpn after enabling IPv6 on tunnel for IPv4 or IPv6

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I'm trying to enable IPv6 on my OpenVPN tunnels, but when I follow https://community.openvpn.net/openvpn/wiki/IPv6 and add

openvpn --version

OpenVPN 2.4.0 mipsel-unknown-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [MH/PKTINFO] [AEAD] built on Feb  3 2017

openvpn windows client

peer info: IV_VER=2.3.11
peer info: IV_PLAT=win
peer info: IV_PROTO=2
peer info: IV_GUI_VER=OpenVPN_GUI_10

openvpn linux client

peer info: IV_VER=2.3.14
peer info: IV_PLAT=linux
peer info: IV_PROTO=2

Working Config

daemon
topology subnet
server 192.168.12.0 255.255.255.0
proto udp
port 1194
dev tun21
ncp-ciphers AES-128-GCM:AES-256-GCM:AES-128-CBC:AES-256-CBC
cipher AES-256-CBC
auth RSA-SHA384
compress
keepalive 15 60
verb 3
push "route 192.168.11.0 255.255.255.0"
client-config-dir ccd
client-to-client
duplicate-cn
push "dhcp-option DNS 192.168.11.1"
plugin /usr/lib/openvpn-plugin-auth-pam.so openvpn
verify-client-cert none
username-as-common-name
ca ca.crt
dh dh.pem
cert server.crt
key server.key
status-version 2
status status 10

But if I add:

server-ipv6 2001:db8:0:123::/64

Although I have an IPv4 and IPv6 IP on my client, I cannot send/receive any traffic.

I've tested on v4 Only and Dual-Stacked v4/v6 endpoints, I currently only need to provide v6 connectivity over v4 tunnels, but eventually the reverse.

openvpn ipv6 ipv4

1 Answers

  1. Got it working and fixed 2 issues.

    1) I'm pushing the compression var

    comp-lzo yes
push "comp-lzo yes"

    2) And added tun-ipv6 options

    tun-ipv6
push tun-ipv6
server-ipv6 2001:db8:0:123::/64
push "route-ipv6 2001:db8:0:123::/64"
push "route-ipv6 2001:db8:0:10::/64"

    where 2001:db8:0:10::/64 is my example LAN subnet.

    Helpful Link

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