When you have an SNMP polling service running like Cacti, you can poll your Ubuntu machine's easily in a few steps.

1. install snmpd (snmp deamon)
sudo apt-get install snmpd

2. now edit the settings file
sudo vim /etc/snmp/snmpd.conf

3. comment out when the SNMP polling server is not running on the local host:
#agentAddress udp:127.0.0.1:161

4. add listen on all interfaces for both IPv4 and IPv6 UDP 161
agentAddress udp:161,udp6:[::1]:161

5 option 1. scroll further down and add above "rocommunity secret" (your polling community string "secret" and your polling server ip address i.e.; Cacti):
rocommunity secret 192.168.1.100

5 option 2. or with FQDN
rocommunity ForgeMe123 cacti.example.com

6. Save the config and restart services:
sudo service snmpd restart

Out of the box Ubuntu 14.04 LTS supports stateless IPv6. This means you can run IPv6 without DHCPv6 server. If you want to run an DHCPv6 server to automatically register IPv6 addresses in your local DNS, or you want to port forward certain ports for a service (webserver / bittorrent) to a specific IPv6 address (DHCPv6 reservation) you end up having to set up a DHCPv6 statefull client. This is quiet easy; assuming you've already got an DHCPv6 server running in your network. In this example we're using "wide dhcpv6 client":

sudo apt-get install wide-dhcpv6-client

sudo vim /etc/wide-dhcpv6/dhcp6c.conf

modify the contents of this file so it looks like this:

# Default dhpc6c configuration: it assumes the address is autoconfigured using
# router advertisements.

profile default {
information-only;

request domain-name-servers;
request domain-name;

script "/etc/wide-dhcpv6/dhcp6c-script";
};

interface eth0 {
send rapid-commit;
send ia-na 0;
request domain-name-servers;
};

id-assoc na 0 {};

Just restart the services and you're done.

sudo /etc/init.d/wide-dhcpv6-client stop
sudo /etc/init.d/wide-dhcpv6-client start

 

I've encountered some more errors under Ubuntu 12.04 LTS when issuing "sudo apt-get update":

W: Failed to fetch http://nl.archive.ubuntu.com/ubuntu/dists/precise/multiverse/source/Sources Hash Sum mismatch
W: Failed to fetch http://nl.archive.ubuntu.com/ubuntu/dists/precise/multiverse/binary-i386/Packages Hash Sum mismatch
E: Some index files failed to download. They have been ignored, or old ones used instead.

Easily fixed with:

apt-get clean
rm -rf /var/lib/apt/lists/*
rm -rf /var/lib/apt/lists/partial/*
apt-get clean
apt-get update
apt-get upgrade

Could be relevant for to other Debian-like Linux.

Recently I've encountered an error when issuing "sudo apt-get update" on Ubuntu 14.04 LTS:

W: GPG error: http://download.webmin.com sarge Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D97A3AE911F63C51

An easy fix which worked for me was:

sudo gpg --keyserver pgpkeys.mit.edu --recv-key D97A3AE911F63C51
sudo gpg -a --export D97A3AE911F63C51 | sudo apt-key add -

The problem and fix could apply to other Debian-like Linux.