Mysteries revealed
In one day I’ve resolved two mysteries…
Mystery #1: why some machines could connect to the SMTP mail server and some couldn’t?
I’m trying to get our Moodle server connecting to the universities email server, so it can send out forum subscriptions, forgotten passwords and other notifications, making the whole site much more useful.
I spent most of the day yesterday with Girmay in the uni’s ICT dept tryng to figure this one out. We eventually discovered that only unix machines were able to connect, the Windows machines we tried couldn’t. So we then set about looking for a rule on the network, firewall or smtp server which disallowed connections from Windows. We knew it wasn’t an IP based setting as my desktop is dual boot and is set to have the same IP from both Ubuntu and XP and I could connect from Ubuntu but not XP.
I also emailed some of the other VSO IT volunteers about the problem and got a reply that it was probably the Windows firewall or anti-virus program that had been stopping the connection. On investigation all the Windows machines we’d tried were running McAfee and this was preventing outbound SMTP traffic. I’d been looking at the problem from the wrong end in the first place, assuming it to be a network or server issue rather than on the client.
With that resolved I now just have to figure out how to make the SMTP server relay to addresses other than the local @mu.edu.et domain, but without creating an open email relay(spammers heaven!).
This highlights a problem some of the other IT volunteers have been discussing over the last few weeks – the fact that when we arrive in an institution we’re expected to be experts in all aspects of IT – which, quite obviously, we aren’t. As my issue demonstrates, we can each waste a lot of time trying to fix problems others could fix very quickly.
Mystery #2: Why, when the water supply is off, we’re not being supplied from the water tank on the roof?
We’ve been having lots of problems with water supply recently, frequently none being supplied at the weekends. Someone from the water company said that our meter was going to be replaced, but no other explanation.
When the water suply in our area is off, we ought to be supplied from whatever is in the water tank on the roof (until that runs out of course), but this hasn’t been the case, once the water goes off that’s it. At first we thought it may be that the water has been off for several days and as we’ve been using the tanks supply we’ve not noticed – but this isn’t the case.
On getting home from work today, I found the water meter spinning very fast *backwards*, then realised what the problem must be. A valve in the meter must be broken, which explains why the meter needs to be replaced. When our water supply stops, or the pressure drops enough, all the water in our tank empties back out to the main supply. The inlet to the tank is at the bottom rather than the top – for some reason unknown to me.
Turning the stopcock off stops our water tank emptying back out. Just need to remember to turn it back on when the pressure increases again.
Next mystery to resolve is why my Dads PC can’t read the DVD of photos (jpgs) I posted home… even though they opened fine on my laptop…
