Hands on: Troubleshooting remote access

Too much protection
Another user at the same company also came up with a weird problem which took a lot longer to resolve, this time migrating email to a newly purchased notebook.

The user here was using Outlook as his client, pulling messages down from the company mail server to a local personal folders (.pst) file using Pop3.

However, because he wanted to access his mail from home as well, we needed to switch him over to an Imap account, where messages are left on the server.

So, we configured a new install of Outlook on the notebook, then took the option to import existing Pop3 messages from the old one. That’s a process which should have taken just a few minutes over the 100Mbits/sec Lan connection involved, but which dragged on for over an hour before I stopped it.

The same happened when I tried a second time, so I switched tack and simply copied over the .pst file from the old PC, the idea being that we could then drag and drop into the new Imap folder. However, Outlook then struggled to open the copied .pst, with a lot of disk and processor activity but nothing much happening on the screen.

It looked as though there was something wrong with the .pst file itself, but compacting it had no effect. Moreover, the same version of Outlook was being used on both PCs to open the same .pst file.

The cause turned out to be the free anti-virus software which came pre-installed on the new notebook. Because this hadn’t ‘seen’ any of the hundreds of messages in the Outlook personal folders file, it was furiously trying to scan each one on the fly when I either tried to import them or open the file directly.

Turning it off solved the problem, after which I installed the normal anti-virus client used by this company, and all was well. It just goes to show that sometimes free software can cause problems that are hard to track down.

Lan over power
I’ve been playing with some more Homeplug/Powerline kit and was impressed by how easy it is to build or extend a network using these products, and the level of compatibility when using devices from different vendors.

The products I was sent this time were from a company called Vesenet, distributed in the UK by Solwise. I looked at a single-port Vesenet PLA-85-E (£27.45 inc Vat) and a 3-port switch, the PLA-84-3E, which sells for £40.19 inc Vat. Both offer up to 85Mbits/sec Ethernet networking over ordinary domestic AC wiring with optional 56-bit DES encryption, for those worried that someone might be able to hack into their networks over the National Grid.

At least two Homeplug devices are required to create a network, but all you have to do is plug them into a mains socket and they will locate each other and establish a connection automatically. Unfortunately they are quite bulky, which can cause problems with other devices. For example, it can be difficult to operate the on/off switch and there’s not much room left over for things like AC adapters.

However, the PLA-84-3E is particularly nice in this respect in that it comes with a plug-in lead, rather than being inserted directly into the socket. I’ve also experimented with extension leads. According to most vendors, you’re not supposed to be able to plug Homeplug adapters into them, but in my tests they worked fine.

LEDs light up when other devices are found and a connection has been established over the AC wiring. The adapters can also be on different cabling rings and you can have either fuses or miniature circuit breakers in the consumer unit. Moreover I was able to mix the Vesenet products with others I was already using from Netgear and was more than pleasantly surprised when they simply found each other and started working.

Given that there are agreed standards covering Powerline networks, I guess I shouldn’t be that surprised when products from different companies work together. Still it’s refreshing when they do. I could even manage the adapter encryption using the software provided from either vendor, which turned out to be based on more or less the same code from the Homeplug Alliance.

The only bugbear was a lack of performance. Just as with wireless networking, the maximum bandwidth claimed (85Mbits/sec) simply isn’t delivered. I also got varying results depending on where the adapters were plugged into the mains. However, I did manage an average of around 50-60Mbits/sec which isn’t bad, and it’s a lot better than most wireless setups. For internet connection sharing it’s more than adequate and it also enabled me to share a Nas server with no problems.

I’m also looking forward to trying out adapters based on the Homeplug AV specification. These support a maximum bandwidth of 200Mbits/sec and have additional QoS (Quality of Service) facilities, specifically to handle streaming of high-definition video to remote TVs. I’ll let you know how they perform when I get them.