IPv6 Cheat Sheet

Example IPv6 address: 2a02:04e8:0004:1050:0000:0000:5c3c:795c

IPv6 addresses are written in Hexadecimal and divided into eight blocks, each containing four hex digits. Addresses can be shortened by skipping leading zeros in each block. This would shorten the example address above to 2a02:04e8:4:1050::5c3c:795c

*nix IPv6 Console Tools

• ping6 - IPv6 version of ping
• traceroute6 - IPv6 version of traceroute
• tcpdump ip6 - Packet sniffing tools with IPv6 options
• ip -6 route - View the applied IPv6 route configuration

Windows IPv6 Console Tools

• ping -6 ; IPv6 version of ping
• traceroute -6 ; IPv6 version of traceroute
• pathping -6 ; IPv6 version of route and packet loss trace tool
• route PRINT -6 ; Show IPv6 route settings on host machine

Connecting to IPv6 IPs

Command Line Interface (CLI) - ssh 2a02:04e8:4:1050::5c3c:795c or wget ftp://[2a02:04e8:4:1050::5c3c:795c]

Browser - http://[2a02:04e8:4:1050::5c3c:795c]:8443

Enable IPv6 on some servers

SSH to the IPv4 address of the server, then do:

cp /etc/network/ipv6 /etc/netwrok/if-ip.d/ipv6
/etc/init.d/networking restart

Useful Links & Commands

• http://test.ipv6.com - Browser-based IPv6 connectivity test for users
• http://ultratools.com/ipv6tools - IP Address converters, calculators and lookups
• http://ipv6.he.net/certification - IPv6 tutorial and certification course

Show all listening ports on IPv6:

netstat -lnptu -A inet6

Show IPv6 firewall rules:

ip6tables -Lvn

Append a new firewall rule for IPv6 (example drops all traffic to FTP port):

ip6tables -A INPUT -p tcp --dport 21 -j DROP

Remove a firewall rule (example delete rule 10 as shown by the show command):

ip6tables -D INPUT 10

Logical Troubleshooting

• 1) Can you browser IPv6 through your ISP? http://test.ipv6.com
• 2) Has IPv6 been enabled on the VPS?
• 3) Has the VPS/networking been rebooted to allow services to bind to the IPv6 address?
• 4) Is the link-local IPv6 address pingable on the server? ping6 ::1
• 5) Is the server IPv6 address pingable from the server locally?
• 6) Is the server IPv6 address pingable from the host machine? (for Virtual Machines)
• 7) Is the server IPv6 address pingable from your PC?
• 8) Has the domain/website/webspace/subscription/account been configured for IPv6 in Plesk/cPanel/server control panel?
• 9) Does a AAAA DNS record exist on the name server for the domain?
• 10) Has a firewall rule been incorrectly created in ip6tables?