Category Archives: computers

Goodbye Logmein Free? Or Not?

Today I received an email from Logmein, stating that for Ignition users, we can still continue to use the App to remotely access our computers, even after the 6 months free trial of Pro. Interestingly I do not find the same information at their website. I do however, find their community forum where thousands of users have expressed their respond to the demise of Logmein Free.

Logmein_Ignition

I’ll probably just hang around and see what happens in 6 months. I’ve already got a few other alternatives to use, such as Splashtop, Teamviewer & VNC. And while going through the forums, I discovered Google’s Chrome Remote Desktop, which I’ll find time to try out.

Logmein Free no longer available

end_of_logmein_free

I’ve been a user of Logmein Free for many years now. At the peak of my usage, I even bought the App on the iPad. It’s still the most expensive I’ve ever bought from the Apple App Store. As I logged in today, I received a notification that Logmein Free is no longer available. Due to my loyalty, I have been granted 6months free subscription to the paid Logmein Pro.

This is quite sad as I like their service, and it has been a reliable method for me to access my home PCs remotely. Some months back a limit was imposed on the number of PCs I can access remotely for free. Looks like that is not enough, and Logmein has completely done away with the free service.

Free is always appreciated. However this is for personal use and I don’t need any of the pro features (although they are great in a real support environment). At this rate, I will probably have to say goodbye to the service by the end of the 6 months.

20140203: There’s an update to this right here

USB Drive not working? could be the cable!

Did you have the experience that when you plug in your USB drive to the PC, it doesn’t get detected, or windows give some error, and perhaps the drive doesn’t seem to be spinning up at all? I just did, in fact it happened to 2 of my old drives. A 80GB and a 120GB which I haven’t used for a couple of years.

I thought that they were old and were failing, or already had failed. Turned out to be otherwise!! It was the USB cable I was using. The cable was meant for those drives, but due to the age and the humidity of Singapore, the contact points of the connectors had some level of corrosion. Interestingly, it’s bad enough to not deliver enough power to spin up the drives and to cause unusual behaviour. Once I switch to a good cable, the drives spin into full life!!

So, lesson learnt, if your USB drive seems not to be working, try and change the cable first.

Aztech Homeplug HL115EP

I’ve been using the Aztech homeplugs for over 3 years now. Started with the HL109EP, used it for some time, and then several months back I upgraded to the HL115EP.

My preference for home networking connectivity is Cat5e UTP cables. However, when I moved into my current apartment in 2008, renovation works was kept to a bare minimal, and so to run new wiring was not an option. The next best thing was to leverage existing cables.

My apartment has 2 levels with the core internet access point in a far end of the apartment. Wireless reach is poor, and I had to extend it. Wireless bridging didn’t give good performance, and would require several Linksys WRT54GL (my old time favorite hacked with DD-WRT) to cover the whole apartment. So, the other alternative was with physical connectivity, which cleverly uses the power lines that reaches to every corner of the apartment.

The Aztech homeplugs were introduced, and worked pretty well. The electric cabling around the house became the core network backbone of my home network.

With the HL109EP, which on the box rates to be 200Mbps, was able to deliver up to 36Mbps with the power points on the lower level, and about 17Mbps on the higher level. The reason was how the electrical connection was done; there’s a big hop from the lower to upper level.

The LAN port on the HL109EP was 100Base-T, which is very common. If you are thinking now, how will 100Base-T give 200Mbps, it’s the common marketing gimmick of adding upstream (100Mbps) and downstream (100Mbps). As my internet connection back then a 10Mbps (ADSL), that was good enough. Anywhere in the apartment I could make use of the full bandwidth of my internet line.

Earlier this year, I upgraded to 50Mbps Fibre. That puts the “core network” to be the bottleneck. The reasonable option was to upgrade. Quite coincidentally, Aztech launched the new HL115EP. On the box it says 500Mbps, and the device has a 1Gbps LAN port. How this has improved is that the device has a built in noise filter. This will effectively improves on the quality of the signal the HL115EP can deliver over the same wires, and therefore achieving higher speed.

The performance of the HL115EP is definitely noticeable. In my case as a 1 to 1 replacement of the HL109EP it gives me double the throughput. At times it can go faster up to 3x but that really depends on how noisy the power lines are.

One thing to note is that the HL115EP does not work with the HL109EP, they will not talk to each other. However, if you have multiples of each, and need 2 discreet networks, that will work just fine. So say if you want to have 2 networks on the same premise that do not talk to each other, you can have one network made up of HL109EP, and another of HL115EP.

I don’t have experience with other competing products and cannot compare. But what I can advise is that keep your Powerline networking gears to be consistent throughout. Don’t attempt to mix and match. I was lucky to be able to upgrade all my HL109EP to HL115EP through an Aztech launch promotion!!

I did say to keep the Powerline equipment consistent; that’s all that really matters. Your internet router, wireless access points, NAS, everything else on the network, does not have to be an Aztech. I have a 2Wire router (provided by my ISP), a DLink Gigabit switch, Linksys WRT54GL, Baffalo WZR-HP-G300NH, Foscam FI8919W, Apple Airport Express connected to various HL115EP and they are working very well.

For those who wonder how I test the network throughput, basically just having a PC/notebook at each end of the HL115EP and run iperf on them.

Anyone in Singapore who is keen to invest in the HL115EP, on tip is Aztech is in every PC show that happens every 3 months in Singapore. You can typically buy a pair for under S$120. Outside the PC show, a pair will cost about S$130 depending on where you shop. Find the brochure of a recent PC show here.

Hello 2012!! The most >Geek< fun I've had in a while

ok ok, so this is really not at all keeping up to trying to post regularly. Got too busy, had a baby, etc.. excuses.

Now, I have a great reason to post!! I just finished a little pet project, tiny one.. but I’m quite excited about it as it’s something I’ve tried to do over 10 years ago, but the products were bad. Now, with newer hardware and software it’s a reality!

I had just succeeded to build my home SIP infrastructure. With a SIP client on my iPhone, I can connect to my personal PBX server, and make calls to regular phones via a SIP to PSTN router.

You are lost? I just built my own VOIP system, which I can make data calls over the air, from my iPhone, connect to my home based VOIP system, and call to a land line. What’s so big deal about that? Here in Singapore, the digital land lines are completely toll free! All outgoing LOCAL calls are free. With 3G and 10GB of quota a month, I can make a lot of phone calls this way!

I will share how I did it… and boy, it’s not easy. This setup is not for the faint hearted to even attempt to consider. Leave it to the real IT geeks *cough*

Here’s a glimpse on what you’ll need.

  1. Home broadband connection which has preferably unlimited usage (as we get here in Singapore)
    +the broadband connection must always be up (otherwise you cannot connect from outside of your home)
  2. Home wifi  network, if you want to make calls via your SIP client in the smartphone
  3. A Linksys SPA 3102 (retailing for about S$100 in Singapore) – this is a VOIP Router
  4. Asterisk – a free PBX Server – run this on an old PC, or a small atom machine, or a virtual machine
    (I run mine as a VMware Virtual Machine)
  5. A SIP client for your PC and/or smartphone
    PC – A good and free SIP client called X-Lite (http://www.counterpath.com/x-lite.html)
    iOS – many choices available, free and paid I use the free client from 3CX (http://www.3cx.com/VOIP/voip-phone.html)

Generally, each item is easy to get up and running, but to get them working together was not easy, especially when you don’t understand half the terms involved. This is one of the craziest situations where I was looking at pages of configuration items and they are mostly abbreviated.

In addition, there are few up to date guides on the net which tells you what to do. I found lots of guides for Asterisk, some very good, but are for older versions. I’m using version 1.8, and there are lots that are now redundant. After all I’ve done to get things to work, I must say it’s actually not a lot of settings we need to make.

Credits will be given when due. I will link to the sites which I found the most useful information.

 

Windows 7 accessing file share error

strange issue came up for me recently, my notebook running Windows 7, stopped to be able to connect to CIFS shares. I keep getting that the “network is not reacheable” error from Windows. Networking wise, it’s incorrect as I can ping the device and I can access the web services on the device.

Some research pointed me to the proliferation of the 6to4 adapters in Windows. These adapters help to route IPv6 over IPv4, and for some reason, I’ve got hundreds of these adapters in my system.

All I had to do is to remove them by disabling IPv6, and the problem got resolved. No root cause here yet, but at least there’s the fix.

So, go to http://support.microsoft.com/kb/929852 and apply Fix #50409 & #50412. Both will need a reboot each time, and then my problem was resolved.

what the hell is speed and duplex?

It’s actually quite amazing that many many many IT professionals out there is actually quite ignorant about some basic network understanding. Perhaps, forgivable if your IT exposure is high up in the application stack… for those who live and breath system administration… and even for those who are network administrators… no excuse at all.

So, what’s this about? This is about fundamental configuration of physical ethernet network connections. Something a vast majority takes for granted. This applies very much to the days of 10/100Mbps networks, which is still very prevalent in current environment, but is slowly going away.

In ethernet, when 2 devices are connected together with a regular UTP cable, they’ll need to communicated at the same speed and mode of transmission. For optimal operations, both ends have got to be operating at the same settings. For speed, there’s a choice of 10Mbps or 100Mbps, and transmission mode is full or half duplex.

If there is speed mismatch, there won’t be any communications at all, and it’s easily corrected. So once you see there’s a link, the speed is definitely a match. However, what’s not obvious at all is that the transmission mode (duplex settings) may not match. And when they don’t match, the result is horrifyingly slow throughput.

So what does full duplex and half duplex mean? It simply means when and how each device is allowed to transmit. In half duplex mode, it means only 1 of the devices is allowed to transmit at any one time. The other just listens. In full duplex mode, both devices are allowed to transmit at the same time. In the very early days of ethernet over UTP, the cores in the wire are shared, such that the transmission cables are shared, as such when more than 1 device transmits, the message on the cable  gets “noisy” and collision occurs.

Imagine, that if at one end, device A is told to communicate at half duplex, and at the other end, device B thinks full duplex is in operation. So, when A is sending out signal to B, and B needs to send something back to A, B thinks it’s ok and sends out the message. A is not expecting anything from B at all, and so is unable to handle the traffic from B. As a result collision occurs. A will keep resending it’s data thinking that it never reached B, and in the end, a whole lot of miscommunication occurs. This causes what appears to be very very slow throughput.

In this day and age, I would say all cat 5 UTP cables and devices are full duplex capable. Also, there is a 5th setting called “Autodetect”. It’s this “autodetect” setting which introduces a lot convenience as well as headache. Personally, I love “autodetect” and advocate the use of it. But by those who don’t understand it, avoids it at all cost. In fact, some IT shops will default to move away from “autodetect” at all costs.

So, why are some network people so afraid of “autodetect”? More often than not, they’ve had bad experience with poor performances due to duplex mismatch. There is some history to this…. when autodetect first showed up, there was interoperability issues between different vendors. Naturally, for that reason, it’s fair to set a standard to avoid “autodetect” as a default setting. But this is something one will observe maybe 15-20 years ago.

Soon after, the IEEE stepped in to resolve this by standardizing how “autodetect” should work. It’s a good thing, but the standardization is quite peculiar. Here’s why….

Autodetect is great with speed negotiation, if there’s no cabling issue, both devices will negotiate at the highest possible speed. Usually no issues here. Even if one end is put to a manual setting on speed, the other end on auto will still get it right.

Then, here comes the fun part… if one end is set manually on the duplex, the end which is on auto will default to half duplex. Yes, half, not full. I never understood what the reason is. But you can see that if someone sets one end to full duplex, the other end on auto will always talk in half duplex. As a result, we have a duplx mismatch, and performance will be bad.

So, if no one takes care to understand why performance tanks when network settings don’t match at both ends, you’ll get an environment without a standard. You’ll see some ports are set to autonegotiate, and some are set to manual… and some do have mismatch and some don’t.

My take is that, if you’ve got fairly recent equipment, just leave everything on default to be on “autonegotiate”. If you’ve got flaky performance, it’s more likely due to bad cabling, and have that fixed. If you are using manual or static type settings, cable issues are less likely to surface, and it’s not obvious that there may be cabling issue at all.