Tag Archives: networking

networking, tech

Linksys LPAC1750C, Cloud Manager, and the mystery of the wifi printer that would not print

I have been testing the Linksys LPAC1750C wifi access point, a mid-price unit aimed at small businesses (or owners of large homes) who want an extensible wifi network with more features than home networking gear, but at a more affordable price than Cisco or other enterprise vendors.

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This unit supports clustering so is really intended for multiple access points managed as one system, but I have only a single access point. Still, it is enough to get a feel for how it works. In particular, I was interested in the Linksys Cloud Manager, which simplifies management and configuration. A five year license comes in the box, and setup is a snap. Just plug the access point into your switch, create an account on Linksys cloud manager, start a new network, enter the serial number and MAC address of your access point, and you are almost done. The only thing that remains is to create one or more SSIDs, which apply automatically to all the access points in your network. VLAN support means you can configure guest networks, and there are options for client isolation and splash screens so that you can display some information to guest users when they log on.

I was impressed with the ease of use, but noticed that the cloud manager has limited features compared to the local browser-based configuration screens. No RADIUS support, for example. You cannot use both, since the cloud manager takes over all the configuration. If you revert to local configuration, everything is reset.

All seemed well, except for a curious problem. I have a wifi connected printer and although it joined the network without any problem, I could not print to it. It was as if it was invisible on the network. Sounds like client isolation (where one wifi client is blocked from accessing other wifi clients), except that client isolation was off. The other odd thing was that rebooting the access point seemed to fix it, and I could print, but only for a short time before it reverted to invisibility.

I called support but no joy. You could try resetting the access point, said the tech person, once I had managed to explain the problem successfully. This wasn’t a problem I could live with, so I did the obvious thing, disabling the cloud manager and using the local configuration.

When I did, I soon spotted the issue. The cloud manager automatically applies the same SSID to both 2.4 and 5GHz radios, which is nice for simplicity but there is an unfortunate side-effect. Although they have the same name, these are really two separate SSIDs, and the LAPAC1750C applies SSID isolation by default.

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The printer, being a few years old, does not support 5GHz wifi connections, so it connected to the 2.4Ghz radio. It was then isolated from a PC, also connected by wifi, trying to print to it directly. You could overcome this by routing printing through a server on the wired network but any direct client to client communication will not work.

The solution is to disable isolation between SSIDs but this option is not exposed in cloud manager. So in my case, cloud manager is not suitable. A shame, since within its limitations it seems nicely done.

Everything works now and printing is fine.

windows

Fixing slow network or wi-fi in Windows 8 with Hyper-V

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I had an annoying problem with my Samsung Slate running Windows 8. I use it while traveling, and every time I connected to a different wi-fi network, or even woke it from sleep while on the same network, I would get several minutes pause while Windows tried access the network. During this time, applications like Internet Explorer and Outlook might freeze and show “not responding” messages. Patience was rewarded though, and eventually the network kicked into life and everything worked normally. Until next time.

This is annoying so what is the reason and the fix? The high level view is this:

  1. When you enable Hyper-V in Windows 8 it makes changes to your networking, including creating virtual Ethernet adapters, and unbinding TCP/IP from the physical adapter. If you install the Windows Phone emulator you also get a virtual Ethernet adapter. If you have wi-fi you also get a Network Bridge.
  2. The consequence of (1) is that networking might not work so reliably after Hyper-V is enabled.

The high-level answer then is to remove Hyper-V. That works, but you might want to use Hyper-V, so better still is to fix the problem.

The answer seems to be in a hidden dialog. To get to it, open Control Panel and search for Network , click View network connections. This will show all the stuff Hyper-V has created. Now press the Alt key on the keyboard to show the Advanced menu, and select Advanced settings.

NOTE: if you have a slate without a physical keyboard, this menu is doubly difficult to find. The Windows 8 touch keyboard has no Alt key. Microsoft decided it was more important to have a Smiley key, and could not fit in both. The fix is to go into Change PC Settings – General and enable “Make the standard keyboard available”. It is still not that easy to display the Advanced menu in Network Connections, but it can be done.

Here is the dialog:

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Now, if you have the problem with slow networking, you will probably find (as I did) that there is an Internal virtual Ethernet adapter, bound to TCP/IP, listed above the external virtual Ethernet adapter. The internal network cannot connect to the internet:

The Internal type is not bound to a physical network adapter. It is typically used to build a test environment where you want to connect to the virtual machines from the host operating system, but do not want to allow virtual machines on the host to communicate with external networks.

It is plausible that if the internal network has priority over the external network, Windows will struggle to connect to the Internet.

I changed this so that the external virtual Ethernet adapter, bound to TCP/IP, comes at the top.

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This has helped with my problem, though there is still a bit of uncertainty about how to optimise the settings in this dialog. What about the Provider Order, what is the correct setting? Should the Microsoft Remote Desktop Session Host Server Network Protocol really come first in the list, as per the default?

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Someone asked on the official forum and did not get an answer. I suggest you leave well alone unless you know better, but would be interested in someone has informed guidance.

Finally, note that if you create a new virtual adapter in Hyper-V settings, you may need to revisit the binding order.

I have never come across this issue on Windows Server, though in principle it might be the same. Odd.

Updated with instructions for enabling the standard keyboard layout.

windows, windows 7

Virtual wi-fi adapter breaks wireless in Windows 7

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Today I was asked to look at a Toshiba Satellite Pro laptop that would not connect to a wireless network. At least, it connected but there was no internet connectivity. I did the usual ipconfig /all and noticed that everything looked OK on the wireless adapter – IP address, default gateway, DNS servers. Nevertheless it could not resolve a ping.

I tried various things – reset the TCP/IP stack, updated the Realtek wireless lan driver, even tried with a different wireless access point, but still it did not work.

Curiously, a wired connection to the same router worked fine. Investigating further, I found that it was possible to ping remote sites by IP number, but not by name. It was a DNS resolution problem. But what? Even specifying the addresses of known good DNS servers in IPv4 properties did not fix it.

I Googled and found this discussion. Ignore the official Microsoft reply. The issue is with this thing:

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This is the Microsoft Virtual WiFi Miniport Adapter. If it is enabled on this machine, then DNS resolution over wireless fails, even though it says “Not connected.” If it is disabled, everything works. So you right-click it, select Disable, and all is well.

Problem fixed; but what is this virtual adapter? Long Zheng has an overview. Essentially, it lets you have more than one wifi connection even with only one physical wireless adapter, which means you can make any Windows 7 into a wireless access point.

This is odd though, because there is no obvious way to connect it. Here’s the reason:

Currently this feature is a development platform that exists only for application developers.

and with a link to this article, which explains how to create a wireless hosted network using the netsh command line utility.

That’s all very well, but it is annoying to find that a user cannot connect at all, thanks to some unknown interaction with an experimental virtual device that is of little practical use.

What I still do not know is how to fix the issue properly, instead of just disabling the virtual device. The problem is not universal; in fact, the netbook on which I am typing this post also has a virtual wi-fi adapter and it does not cause any problems. I doubt the user will suffer any adverse effects from its absence though.

Update: Kelvyn Taylor points out that the handy Connectify utility uses this feature of Windows 7.