wishlist

iPad: 1400

iPhone4: 400?

Bose Companion 5: 750

Bose Dockable : 750

Qnap 8 Bay NAS: 2800

2T HD X8 : 1600

---------------------------

SUM: 7700

How to install dynagen in Ubuntu

Quoted from http://www.blindhog.net/cisco-dynamips-and-dynagen-install-on-linux/

Strictly not for commercial use

How to enable Symantec AV live update that is grey out

Go to

[HKEY_LOCAL_MACHINE\SOFTWARE\Intel\LANDesk\VirusProtect6\CurrentVersion\PatternManager]

add "EnableAllUsers"=dword:00000001
or Change the LockUpdatePattern and LockUpdatePatternScheduling from "0" to "1"

好热的天

哇塞，晚上都热的不行。 还好及时做好了有空调的study room。

又要熬夜

同学A实在是太有精力了。 叫他回收两个模块就好了， 结果给客户提案的时候非要回收3个。 这好了， 2个在左边的DC， 1个在右边的DC。 两个DC之间有10公里。 扼腕墓道的是， 多回收出来那个模块又完全用不上。 同学A说， 不好意思啦， 要你帮忙了。。 这样好了， 你去左边的DC， 比较简单。。 我faint.. 刺痛我的是白熬夜这回事。 杯具了。。

打印机挂了

昨晚打起精神来设置打印机。。 本来store room位置就很小， 纠结了很久总算决定把打印机放在3560上面。。 费了一番心思把线都走好， 然后打开电源。。 啪！ 一声很清脆的炸裂声终结了打印机的某个原件。 杯具啊。。

eBGP split horizon?

This is a interesting case that is often overlook. The question is: when A BGP speaker receives an update from its upstream(eBGP) and install it as best route, does it turn around and advertise it back to the upstream speaker?

I bet most of the ppl will say "no". In fact, hey, what is the point of advertising the route back to someone who knows the route better than you?

Interesting thing is, it depends. When the BGP speaker receiving the route from upstream is Multi-homed, and if it has not configured any outbound policy, it does advertise the same route back to its upstream. Of course the upstream will drop it due to AS loop prevention. I am not sure whether this is a protocol design, or something that is not well defined and Cisco implements it that way.

Such behavior has some adverse effect. The first one in mind is the unnecessary update sent back to the ISP. Imagine the ISP sends 10k route to the Transit router (in most case also customer owned), then 10K route is reflected back to the ISP. Although it is eventually dropped, it does waste processing power and may potentially trigger alerts unnecessarily.

I was hit by the second adverse effect when i am doing a design mock up for customer's MPLS VPN in campus. The simplified version of the network looks a bit like this:

The interesting thing here is that to fulfill MPLS PE/CE route exchange requirement, PE2 has to enable feature allow-as-in (assuming CE 1 is the fusion router routing all VRFs), this breaks the AS loop prevention mechanism. Together with the fact that the VPN routes from remote site are all iBGP routes which is by default very much less preferred, a routing oscillation is observed when CE1 sends the same route back to its upstream (PE1) under the same VRF. Of course the remedy is not that much of rocket science. Just tag the outbound routes from PE2 using any means and configure outbound filter on CE1 to stop the same route under the same VRF from sending back to the MPLS BB will do.

But if you have logging console debuging turned on (mostly default), be prepared to see 99% CPU utilization when you leave the deb BGP update on. :D That should wet quite a lot of pans if it is production

我的新窝

折腾了好阵子， 终于有了自己的工作娱乐角了。一个2.5乘1.4的Store room.

框架是从宜家购入的铁架床， 床下就是工作空间。

桌子是特别从lizo定做的， 1.8乘1.2m, 放在床下面刚刚好。

由于空间实在有限， 把床垫放上去的时候还要把床架拆掉一部分， 动员了全家5口人才完成的， 真是是劳师动众， 也非常感恩。 床垫不是一般的舒服， 呵呵。

一切都好， 除了空调有点吵。

disable backup on iphone

自从买了iphone以来一直对apple product 的人性化设计为之叹为观止， 可是偏偏这个itune就是特别的难用。 每次sync的时候一定要吧整个iphone的东西backup起来。。 我的iphone大概也只放了3-4G的data, 那个backup 已经是不能再龟速的龟速。 而通常我想要sync的东西也只是calendar而已。。 比较FT的是， itune竟然没有一个option可以在sync之前disable 掉这个backup. 想要disable掉这个backup, 居然还要付诸于类似改registry的方法：

Disabling the slow iTunes Backup on Windows is a little more tricky, but it works. First of all close ITunes and then follow these steps:

1. Locate your iTunesPrefs.xml file. It’s usually located in C:\Documents and Settings\username\Application Data\Apple Computer\iTunes or C:\Documents and Settings\username\Local Settings\Application Data\Apple Computer\iTunes.

   Hint: If the folder Application Data does not show up, make sure that hidden files are visible in the Windows Explorer

2. Backup your iTunesPrefs.xml file
3. Open iTunesPrefs.xml using a capable text-editor (e.g. Notepad++, Ultraedit, but not MS Notepad)
4. Search for a section called User Preferences and paste the following snipped into the User Preferences Section after the first :

   DeviceBackupsDisabled

dHJ1ZQ==


   After you've done that it should exactly look like the screenshot on the left.

5. Save the file and restart iTunes. Backups should now be disabled. To enable backups again delete the XML Snippet from iTunesPrefs.xml file.

Wake up your PC from internet

Wake up on lan technology use special "magic" packet in order to "wake up" a "sleeping PC" in a LAN environment. This packet can be UDP or ICMP, wake up software dependent. For the solarwind, it is using UDP port 7. See below sniffing:

Convention wisdom tells us that to use wake up on lan, the wake up on lan packet must be sent to the broadcast address of the segment where the PC to be woken up sits. Reason for this is apparent: The wake up packet must reach the sleeping PC. However a sleeping PC does not do ARP, hence the switch does not know where the sleeping PC is. Sending the wake up packet to the broadcast address (ip and mac) solve this problem nicely, or sort of.

But how do I wake up my PC when I am not at home? 192.168.40.255 does not work for me. Port forwarding? No way.. you can't translate the gateway IP to a broadcast address. But we do have a trick.

Remember the objective of sending the wake up packet to broadcast address is to ensure the sleeping PC gets the packet because it does not do ARP? How about creating a static CAM entry on the switch since we know the sleeping PC's MAC? Hmm.. sounds great but I am using some cheapo 50 bucks switch. We need a poor man solution. Let's see.. what happen to the switch when it sees a MAC where it can't find a hit in its CAM? It floods to all ports.. bingo! Why bother to do the static CAM?

Hence the solution is to create the following PAT entry at the ADSL router:

gateway_IP:outside port-> phantom_IP:inside port

in out case, it will be 119.x.x.x:7->192.168.40.144:7. The phantom IP is one that no one uses. Then create static arp to force binding between "phantom IP" and the "sleeping pc"'s MAC (Ensure your gateway ADSL router can do this):

192.168.40.144->0024.8C51.0661 (sleeping pc's mac)

Then what's left is to run the wake up on lan software, key in IP address 119.x.x.x and.. if things works well, you will find your PC reachable soon from your mstsc while u sitting at East Coast MAC. :)

实在不能忍受MSN那个不能分类的BLOG

google 就是比较厚道， 东西不要钱也做得比M$好几倍。 就拿这个text editor来说好了。。 M$的巨慢还整天crash。。 这个editor 居然连上传的图片也可以cut and paste。 真的神了。

label的作用还是很显著的， 不过还是没有我想象中的树状分类， 可惜