October 2006

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Thursday afternoon we started to receive reports of high latency and packet loss on ResNet. It would appear that the main link between ResNet and the internet is having a few problems, and has fallen over to a backup link. Unfortunately, it fell over in such a way that our monitoring software didn’t spot it happening!

The backup link doesn’t have our sophisticated trafic shaping hardware running on it, and as such the link is being swamped by P2P traffic. Here’s a graph:

Traffic Graph - 15th Oct onwards

As you can see, the problems started at about lunchtime on the 26th, and our offsite traffic pretty much doubled! This network congestion explains why people are seeing high latency and packet loss.

Now that we’re aware of what’s going on, we’re working on a fix.

Update: All fixed! Our traffic levels are back to normal again, and the link is now much less congested.

This email is being sent to all ResNet subscribers with tips and advice to get the most out of your connection. You can also read it on the ResNet blog – http://www.bristolresnet.net

Manage My ResNet

Did you know that from our website you can view and update your ResNet account details – check your subscription period, move your ResNet connection to another room, or connect a different computer to your socket? Go to Manage My ResNet http://www.resnet.bristol.ac.uk/myconnection/ to try it.


Do you know what is really running on your computer? Without your knowledge you may have spyware. If so your computer may slow down, get lots of pop up adverts, extra toolbars, your home page keeps changing or you get sent to unwanted websites.

The main purpose of spyware is to give you extra advertising. As part of this it collects and reports back your personal information such as what websites you visit, invading your privacy. Sometimes it breaks your Internet connection completely.

To avoid spyware only download software from sources you trust, keep your system up to date, and don’t click on links in spam or pop-up ads. You can also install free anti-spyware software such as WindowsDefender http://www.microsoft.com/windowsdefender/ For more info see our Spyware advice page http://www.bristol.ac.uk/is/computing/advice/homeusers/security/adware.html

Firefox – a better web browser

Most people use Internet Explorer to browse the web. Why not try Firefox – a better web browser, and it’s completely free! For starters Firefox is much better protected against spyware than Internet Explorer. Get a copy of Firefox from http://www.getfirefox.com or from the CD in your ResNet pack.
To get Firefox to work on ResNet you need to tell it to use our web proxy server – we have an easy tool that does this for you. See configure your browser http://www.bristol.ac.uk/is/computing/advice/homeusers/resnet/connect/config/web.html

The router (a cisco 857) was installed yesterday at about mid-day.  We experienced some strange behaviour (high latency and occasional disconnections) that lasted until about 5 am this morning. We believe that this was due to the router negotiating the best possible speed from the dsl link.

The connection now appears to be stable and relatively quick.

To all residents at Hillside/Woodside:

copy of letter sent by post last Friday. 

Dear resident,

I’d like to apologise for the lack of an Internet connection at Hillside/Woodside so far this term. We will very soon be providing an ADSL connection for the house, which should be available by Fri 20th October. We will update you when the connection is ready for use, this is simply some advance warning. 

There will be no charge to use the ADSL connection. We will provide network cables – to use it all you essentially need to do is connect the cable from your computer to your wall socket, and make sure your computer is set to “obtain IP address automatically” (the usual setting). 

This is a shared connection, and will operate at a likely speed of 1 Mbit/sec, which is not much between 30 people. It should be adequate for email and web use, but not other applications. Anyone attempting to use filesharing programs to transfer large movies, music and other large files will completely swamp the connection and cause problems for everyone else. Please don’t do this! It is up to you as housemates to use the connection sensibly, we can’t enforce it.

The ADSL connection is a short-term measure and not up to the usual ResNet standards. We have a dedicated 10Mbit leased line on order for Hillside/Woodside, but installation of this is still some time off (we don’t have a confirmed date yet, but it should be some time in November or December). When this line is installed we will be able to offer a faster service, similar to ResNet in other student houses, and will begin collecting ResNet subscriptions at that point.

For anyone who has already paid a subscription to ResNet  partial refunds may be available, but we will work these out when the faster connection is in place.

We now have over 4000 students successfully connected to ResNet. That’s about 85% of the total in residence, within the first two weeks.If you haven’t yet connected, please ask your hall office, porters lodge or senior resident for your ResNet pack and use that to connect. If you need any help connecting, you can phone the ResNet Help Desk on 89001 (free internal call from your room).

ResNet uptake - first two weeks

ResNet Chat

ResNet Chat is new for ResNet this autumn. It’s an instant messaging program especially for Bristol students. There are chatrooms for each hall, and a special Orbital (students out of hall) room for the student houses. You can add your friends as private contacts, see when they are online and message them. See www.resnet.bristol.ac.uk/chat to try it out.

Changing your initial password

If you are a new student you will have been given an initial password as part of registration. If you haven’t already done so, you need to change your password as soon as possible to something only you know. If you don’t change your password your account will be locked – you will need to change your password at Change UOB domain password before you regain access to computing facilities. You can change your password before or after your account is locked – but it’s a good idea to do so beforehand.

Friendlier email addresses

Did you know that you can choose an easy to remember personal email address at the University? For example, instead of having jd5432@bristol as your mailname you could be Jon.Davies.05@bristol. To choose your own personal mailname go to Request for personal mailname

We lost the ADSL connection with Rodney Place again yesterday at about 17:30. I had to manually reset the connection this morning at 09:20. I am going to investigate ways of automating this, so we do not need any manual intervention. The link is now up and running.


10.30am Monday morning: we had pretty severe problems over the weekend which at various points meant that people were unable to send email, register as new ResNet users, or access our website. Although this was severe some ResNet subscribers wouldn’t have noticed as most of what they wanted still worked – people could still access the web for example.
There were different faults at different stages, but they were all due to problems with our DNS setup. DNS is the system which maps server names to their numeric IP addresses – so without dns the servers are inaccessible.
Right now things are looking quite a bit better but we are checking through everything carefully and ironing it all out. We have the whole ResNet team available and backup from other IS staff too, so can get things sorted. After the dust has settled we’ll review what happened carefully to try and stop something similar happening again.


UPDATED: Tuesday 10/OCT/2006 -  We are in the process of resyncronising our DNS servers and various databases. This may have prevented some people from sending email this morning, but all should be fixed by this afternoon.


Since approx 6.30pm tonight we have been experiencing severe problems which are stopping new people registering on ResNet. Existing people up and running are fine, although there are some parts of our website such as the knowledgebase which are inaccessible.

This is due to a fault with our dns server which we are tracing and trying to fix at the moment.

UPDATE 8.30pm: we think we’ve now fixed the DNS problem, however as DNS information takes a while to propogate it will take a while longer (maybe up to an hour) until everything is back to normal.

Sorry to everyone who was trying to register tonight – please try after 9.30pm tonight or tomorrow.

UPDATED UPDATE – 10:08pm: It’s still somewhat broken. A number of DNS entries haven’t propegated properly, and as such people still can’t register. I’m looking into it.
– Paul

UPDATED UPDATED UPDATE – 10:48pm: I think I’ve identified the problem, but it’s not something I can fix. With a bit of luck, the chap who can fix it will read the email I’ve just sent him. Sorry everyone!
– Paul

SAT MORNING 10AM: Everything now seems to be in the DNS that should be – haven’t spotted any problems so far. Thanks James who was fixing stuff at 4 in the morning!

SAT MORNING 1.30PM: It’s not fixed after all! Registrations are failing towards to end of the process with an error

Can’t call method “ReadMAC” on an undefined value at /var/www/register/cgi-bin/activate.account.pl line 607.

We’re trying to fix it. Please try in a few hours or tomorrow.

SAT AFTERNOON 3PM: Looking better – we’ve tweaked things (added all the hubs to our hosts file) and 12 people have now registered in the last half hour. We’re still testing stuff before we conclude that everything is sorted.

SAT EVENING 6:33PM: Looking worse again! The database job that creates the DNS file has started failing in a pretty catestrophic way and is generating empty DNS configs. So we’ve effectively lost 99.9% of our DNS records. I’m working on a fix. -Paul

SAT EVENING 7:37PM: OK, I’ve now managed to get the database job to produce some output. I’ve taken a snapshot of the config files. The job is due to run again in about 3 minutes time, if it fails, I’ll rollback to the snapshot and turn the job off. This will cause problems for anyone who registers after the sanpshot was taken, but at least it’ll get the service back for the other 3800 of you! -Paul
SAT EVENING 8:38PM: Rolling back to the snapshot doesn’t seem to have helped the situation. The config files are all there, but the DNS entries don’t appear to be propagating. I’m still in the office though, and still working on it… -Paul
SAT EVENING 9:15PM: It’s still broken, but I’ve run out of ideas. As far as I can tell, it *should* be working – but isn’t. Hopefully one of the other guys on the team will have more luck. -Paul

If you’ve been trying to register in Old Clifton Wing CHH or K Block Churchill and had problems, this is because the room numbers have been changed. We’ve now updated our database with the correct info and you should be able to register OK.

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