Showing posts with label MIGRATED. Show all posts
Showing posts with label MIGRATED. Show all posts

Tuesday, March 10, 2015

Learn for Free

Not just technical skills...


Coursera is one of my favorite places to learn a new topic or even expand my horizons on topics with which I am already familiar.  The pacing of a real class structure, with weekly lectures and homework, applies just enough pressure to keep me motivated throughout the class and permits just enough flexibility to fit it into my real-life schedule.
Coursera is an education platform that partners with top universities and organizations worldwide, to offer courses online for anyone to take, for free.

https://www.coursera.org/




I believe this is a trend we will continue to advance as more and more colleges and universities open up classes for free.
Open.Michigan is a University of Michigan initiative that enables faculty, students, and others to share their educational resources and research with the global learning community.

http://open.umich.edu/


Tuesday, February 21, 2012

Enabling IPv6 on CentOS 5.6


Some additional information about IPv6 support and configuration is available from the CentOS wiki at:
http://wiki.centos.org/FAQ/CentOS5
These are the steps I followed to get IPv6 to work.
Edit the network file:
vi /etc/sysconfig/network
Set IPv6 networking to ‘yes’:
NETWORKING_IPV6=yes
Exit and save these changes.

Option 1, EUI-64 auto-assigned IPv6 address:

Edit the interface file:
vi /etc/sysconfig/network-scripts/ifcfg-eth0
If you want to have an auto-assigned IPv6 address based on EUI-64 auto-configuration:
DEVICE=eth0 ONBOOT=yes BOOTPROTO=none HWADDR=00:13:21:0D:0D:B9 # Required for EUI-64 auto addressing. DHCP_HOSTNAME=v6LAB-WWW1.opr.test.statefarm.org IPV6INIT=yes # Enables IPv6 addressing on interface. IPV6_AUTOCONF=yes # Enables EUI 64 auto-addressing. #IPV6ADDR= #IPV6_DEFAULTGW=
HWADDR and DHCP_HOSTNAME should be updated to match the specifics of each server but is likely automatically configured from install.
Exit and save these changes.

Option 2, static IPv6 address:

Edit the interface file:
vi /etc/sysconfig/network-scripts/ifcfg-eth0
So it the file should look something like this:
DEVICE=eth0 ONBOOT=yes BOOTPROTO=none HWADDR=00:13:21:0D:0D:B9 # Required for EUI-64 auto addressing. # Optional for static. DHCP_HOSTNAME=v6LAB-WWW1.opr.test.statefarm.org IPV6INIT=yes # Enables IPv6 addressing on interface. IPV6_AUTOCONF=no IPV6ADDR=AAAA::260:3EFF:FE11:5001 IPV6_DEFAULTGW=AAAA::260:3EFF:FE11:6780
HWADDR, DHCP_HOSTNAME , IP6ADDR, and IPV6_DEFAULTGW should be updated to match the specifics of each server.
Exit and save these changes.
Restart the interfaces with the new options:
service network restart
If there is no error message, IPv6 setup is complete. Jump to IPv6 Test and Validation.
If you get this kernel error:
CRITICAL : [ipv6_test] Kernel is not compiled with IPv6 support
See the section for Enabling IPv6 on CentOS 5.6 Kernal (if needed).

Enabling IPv6 on CentOS 5.6 Kernal (if needed)

The kernel options to support IPv6 on the Ethernet modules need to be enabled. Edit the module probe configuration file:
vi /etc/modprobe.conf
Search for these two lines and comment them out if they exist:
#alias net-pf-10 off #alias ipv6 off
And change this one from ‘1’ to ‘0’:
options ipv6 disable=0
So these lines look like this:
#Uncomment the next two lines to disable IPv6 support at boot. #alias net-pf-10 off #alias ipv6 off #Swap commented/uncommented lines below to disable IPv6 support at boot. #options ipv6 disable=1 options ipv6 disable=0
The only way for the new module options to take place is by a reboot:
shutdown –r now

IPv6 Test and Validation

With IPv6 enabled, we can confirm the interface has at least two IPv6 addresses. A global and a link(local) address:
[root@v6LAB-W1 ~]# ifconfig eth0 Link encap:Ethernet HWaddr 00:13:21:0D:0D:B9 inet6 addr: aaaa::213:21ff:fe0d:db9/64 Scope:Global inet6 addr: fe80::213:21ff:fe0d:db9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:63 errors:0 dropped:0 overruns:0 frame:0 TX packets:96 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6813 (6.6 KiB) TX bytes:15909 (15.5 KiB) Interrupt:209 Memory:fdef0000-fdf00000
We can ping the router (like Windows, the command is ping6):
[root@v6LAB-W1 ~]# ping6 aaaa::260:3eff:fe11:6780 PING aaaa::260:3eff:fe11:6780(aaaa::260:3eff:fe11:6780) 56 data bytes 64 bytes from aaaa::260:3eff:fe11:6780: icmp_seq=0 ttl=64 time=0.594 ms 64 bytes from aaaa::260:3eff:fe11:6780: icmp_seq=1 ttl=64 time=0.541 ms 64 bytes from aaaa::260:3eff:fe11:6780: icmp_seq=2 ttl=64 time=0.529 ms 64 bytes from aaaa::260:3eff:fe11:6780: icmp_seq=3 ttl=64 time=0.546 ms --- aaaa::260:3eff:fe11:6780 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3001ms rtt min/avg/max/mdev = 0.529/0.552/0.594/0.034 ms, pipe 2 [root@v6LAB-W1 ~]#
If we console into the router, we can ping our new server:
v6LAB-R1# v6LAB-R1#ping aaaa::213:21ff:fe0d:db9 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to AAAA::213:21FF:FE0D:DB9, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/4 ms v6LAB-R1#
And ssh to it:
v6LAB-R1# v6LAB-R1#ssh -l root aaaa::213:21ff:fe0d:db9 Password: Last login: Wed May 25 05:48:50 2011 from localhost6.localdomain6 [root@v6LAB-W1 ~]# [root@v6LAB-W1 ~]#

Apache/HTTPD configuration

No special configuration is necessary to enable IPv6 requests on Apache.
After installing Apache, it needs to be set to start at boot using this command:
[root@v6LAB-W1 ~]#chkconfig --level 2345 httpd on

Monday, October 10, 2011

Tweet forwarded by @russruns

cmross: Will seek this out later today.  Steve Jobs banner in the Windy City a nice tribute http://t.co/UjlQ2eG0 via @zite
Original Tweet: http://twitter.com/cmross/status/123434197460324352
Sent via TweetDeck (www.tweetdeck.com)

Tuesday, October 4, 2011

F5 LTM GTM IPv6 quick hit

Just quick note, F5 products LTM and GTM work just great with IPv6.  But IPv6 address shortening (double-colons '::') is not permitted in the GUI or tmsh.
LTM and GTM are Linux based systems, so if you are using BASH, the standard rules apply.
But if you are using the GUI or tmsh, IPv6 addresses must be fully completed.
This:
fe80:0:0:0:201:d7ff:fed4:d041
Not this:
fe80::201:d7ff:fed4:d041     ^^  Cannot have a double colon.

Tuesday, September 13, 2011

So you've got IPv6...

...now what?

This site contains a list of websites with verified IPv6 connectivity. Regularly updated and tested. Also provides the resolved IPv6 address so you can perform basic ping testing in case your DNS is flaky (anyone else have this problem?).

Global IPv6 Deployment Progress Report

Haven't ruled out a problem on the local end, but we do get better (but not 100%) responses from:

Public DNS servers:

  IPv6 IPv4
Open DNS 2620:0:ccc::2
2620:0:ccd::2
208.67.222.222
208.67.220.220
Google Public DNS 2001:4860:4860::8888
2001:4860:4860::8844
8.8.8.8
8.8.4.4