October 2008

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Microsoft yesterday released an extremely urgent update for Windows.

Normally the most reliable way to get updates from Microsoft is to use the Automatic Updates feature in Windows which will install updates for you. On this occasion however we strongly encourage everyone on ResNet to go to the Microsoft Update website or open Control Panel, Security Centre and check for updates. Install all critical or important updates. Do this now, rather than waiting for automatic updates.

This particular update is unusual: it is for a particularly nasty security problem. Any Windows system with File & Printer sharing switched on is vulnerable, and criminals are already using this problem to attack computers.

One of our ResNet DNS servers has developed a disk fault.

The majority of ResNet users will not be effected, as our other DNS server is ticking along nicely – however some users will notice that web usage feels a little unresponsive as their computer tries the dead server before failing over to the live one.

We swapped out the disk this morning at about 10am, in what should have been a transparent procedure with no expected downtime.  Things don’t appear to have gone to plan, and the service is taking longer than expected to restore (as we’ve had to take the server offline while it re-synchronises its disks)

I’ll update this post when we’re back in business.

Update: 12:31
The disks are still syncing – but thanks to some fancy footwork, we’ve managed to move the DNS service over on to a backup machine, so we’ve got two DNS servers again.

Update: Friday 24th Oct – 11:09
Normal service has been resumed – thanks to a significant amount of mucking about with disks, a long and tedious synchronisation process, and an issue with the disk controller drivers.  I do have some more minor work to do to this server to tidy things up – but it’s currently stable so I’ll leave it alone for the weekend.

In order to help prevent a repeat of the ResNet disruption on 20th October, anyone connecting to ResNet with Windows Vista must now have Service Pack 1 (SP1) installed. If you have Windows Vista the online registration process and security checker now check for SP1 and won’t proceed without it.

You need to go through the registration process when connecting for the first time, changing computer, changing room, or at periods during the year.

If when registering you get a message that the code entered is invalid, this is probably because you are using an old version of the security checker. Go through the registration process again and make sure you download and run a new copy of the security checker.

A good way to make sure you are getting the latest version of the checker and not one cached by your browser is:

  1. click the right-hand mouse button on the security checker link,
  2. choose Save Link As/Save Target As,
  3. Type in a new name for the security checker file.
  4. Download and run that new version from the desktop or other destination

We strongly encourage all ResNet users with Vista to install Service Pack 1, even if they aren’t re-registering at this time. The easiest way to do this is to go to Control Panel, Security Centre, WindowsUpdate and install all important and critical updates.

On Monday night between about 7pm and 10pm there are widespread reports of intermittent access to websites. Looking at our traffic graphs sees a significant decrease in traffic. We are currently investigating the cause of this problem and will report back as soon as more information is available.

Update 11.20am Tuesday 21st October: Apologies for the interruption to ResNet last night. We’ve investigated the incident and discovered what happened. Please read on to help us stop it happening again.

A pair of computers connected to ResNet caused a storm of requests to our name servers. Each computer sent thousands of requests every second. This overloaded our two name servers so they couldn’t process anything else. The name servers (DNS servers) are used to look up where to find an Internet server – so without DNS you can’t access anything on the Internet. We are doing everything we can to reduce the impact, but to really solve the problem we need to prevent it at source.

This storm is caused by a bug in the original version of Windows Vista. Any computer with the original version of Windows Vista can cause this, but upgrading to Windows Vista Service Pack 1 fixes the problem. Windows XP & Apple Mac computers don’t have the problem either. To make sure this doesn’t happen again we need everyone on ResNet to check their Windows version, and then install Windows Vista Service Pack 1 if they need it.

  1. Click the Start button
  2. In the Start Search box, type winver and click OK (if you can’t see Start Search, click Run and type winver in there instead).
  3. Look at the version number:
    • If it says Version 5.1 you have Windows XP and don’t need to do anything.
    • If it says Version 6.0  (Build 6001, Service Pack 1) you already have Windows Vista Service Pack 1 and don’t need to do anything.
    • If it says Version 6.0 (Build 6000) you have Windows Vista original and must install Service Pack 1. To do this click Start, Control Panel. Under Security, click Check for Updates. Click to install all important or critical updates. These include Service Pack 1.

For people interested in the technical details of this problem, please see Windows Vista DNS flooding.

Freshers.TV is a new TV channel just launched on ResNet, and running for the next two weeks. It is available

  • on Freewire channel 106 (Windows clients only)
  • on demand at http://www.freshers.tv
  • or in VLC via udp://@

Programmes on Freshers.TV are produced by students at universities around the UK as part of the National Student Television Association (NaSTA).

There’s a movement to launch a Bristol Student TV station too – so watch this space or get involved!

  • Slow, unwell computer?
  • Can’t connect to the Internet?
  • Computer viruses or spyware?

What is the laptop clinic?
At the Student Laptop Clinic we’ll look at your laptop while you wait and help get it working better for you. The laptop clinic is a new service for students at Bristol. We are trialling it this year with generous funding from the Alumni Fund. The people working on the clinic are a combination of other Bristol students and IT support staff.

Where are the clinics?
The Hawthorns Student Refectory – entrance on Woodland Road


Starts Tuesday 7th October 2008, then every weekday 2pm-5pm until further notice.

What should I bring?
Please bring your laptop and power supply. If any Windows or recovery CDs were supplied with your computer please bring them too.

How does the clinic work?
On a first come first served basis. You must stay at the clinic with your laptop.

Who can use the clinics?
All University of Bristol students.

What can you fix?
We’ll look at both Windows & Mac laptops. We can only help with software and configuration problems. We can’t solve every problem, but are happy to look and see what we can do. If we don’t fix it we can also provide advice on what to do next, information to help you fix the problem yourself or suggestions about who else you can contact.

What other help is available?

Don’t forget that you can get help at other times by phoning the IT Help Desk (87870 internal, 0117 92 87870) or ResNet start of term hotline (89001 internal, 0117 92 89001) That’s the first call for help, but for more detailed problems where we need to see the computer you might want to try the laptop clinic.

According to our monitoring system, the ResNet service to 23 rooms at Wills Hall Z Block hasn’t been working since 4.20pm today (Monday).

When this happens it is normally due to a temporary power failure in the affected area – but it has been some time now and there still appears to be a problem, so it probably isn’t just power. Sorry for the interruption to service. We’ll investigate as soon as possible on Tuesday when staff are back in.

Updated 11.35pm Tuesday 7th Oct: ResNet in Wills Hall Z Block is now back up and running

Updated 6.15pm Friday 10th Oct: This failed again overnight on Thursday 9th Oct. The cause on both occasions this week is the power supply tripping out. This power supply is on a shared circuit with some of the rooms on the top floor of Z Block – students in these rooms lost power to their room too. ResNet access was restored when the power was restored.

The usual cause for a circuit to trip out is that it is overloaded, but we don’t know precisely why it is happening in this case.

We discovered a misconfigured setting on the network equipment at Hillside/Woodside this morning. This was responsible for slow speeds and some packet loss over the last week. Sorry about the problem.

The good news is that we’ve fixed this misconfiguration. First reports from residents suggest that the speed is far faster than before.

Background for anyone interested: this year we’ve provided ResNet at Hillside/Woodside for the first time. A dedicated 10 Mbit link replaces the 2Mbit ADSL service which was there before. The new link is provided using a combination of fibre through a new trench and a wireless link across the gorge. This connection is not the fastest on ResNet, but it’s not the slowest either (and Hillside/Woodside has a relatively small number of residents). This connection went in just in the nick of time before the start of term so we didn’t have much time to test it thoroughly, that’s probably why we didn’t find the problem earlier – sorry about that.

It’s the end of Freshers Week – it’s been a busy week but we’re delighted that most new students have such successfully connected to ResNet. If you haven’t been able to connect up yet, the best advice is to first give us a ring so we can help you out over the phone. It is now much easier to get through than it was earlier in the week. The out of hours team are on over the weekend, and the ResNet team back answering calls from Monday.

If you prefer to do things yourself, our tech support people have assembled a list of the most common problems and fixes we’ve seen on the Help Desk. Most ResNet users won’t come across these, but if you are having problems and have some technical knowledge this information will help. If you don’t, don’t worry – give us a ring from your room and we’ll help you out that way.