Fettled any computer stuff today?

[Afasoas]

Got a strange problem at work where occasionally the firewall will pass a broadcast packet from the LAN to the WAN interfaces. The two WAN interfaces don't know where to route the packet, so they just re-broadcast it to each other slowly consuming all the external bandwidth.

By the time we know there's a problem, it's too late to properly investigate it. So I've set-up a box with LAN and WAN interfaces (no IP assigned on the WAN port) to do a rolling packet capture.

This was slightly tricky. Tcpdump doesn't really like running as a daemon, although it does a nice job of rotating dump files. Pcapdump does run as a daemon, but it's idea of dump file rotation is to truncate the file and start again. With a bit of digging around I found dumpcap which is hidden away inside the wireshark-common package. Installed with --no-install-recommends, it's a small install and runs nicely as a daemon.

Hopefully next time around we can capture the broadcast packet from the LAN and try and determine why the firewall isn't dropping it. At least discern enough to try and reproduce the problem.

[woollypigs]

Just as I have been saying that #! is the most stable OS I have run my laptops over the years. The kernel had a hizzy fit and reported that panic occurred and it gave me a black screen of death. Twice in an hour...

[Mr Larrington]

Hurrah!  I have found a faster way of populating my iTunes/Excel SCIENCE.

Bah! It's a bit of a kludge.

 

[tiermat]

Made a mobile more child (and concerned parent) friendly by installing Children Tracker and AppLocker. The moral dilemma created by installing the former is still to be resolved.

[hulver]

Asus T100 transformer netbooks DO NOT BOUNCE.

Especially not off hard tiles.

£25 for new digitser glass isn't too bad (just glad the LCD didn't break as well), and wow, I can't get over how small the circuit board for a full windows computer is. It's tiny! CPU, memory and SSD all on one tiny little board. Very impressive.

I'm not paying £25 for a new back case though. Araldite and a cover will have to do.

[Feanor]

Just fettled a Blu-Ray drive into Junior#2's Alienware 17 lapdog.
The option for a BD drive was not an option on the web configurator-thing when I bought it.

But these things are standard enough, and a bit of google-fu and an ebay order arrived today from Hong Kong.
Not a difficult job to swap it out.

All working well, but I didn't realise slot-loaders have no eject button!
I had to resort to google to discover how you're meant to eject it ( apart from r-clicking on the drive in explorer ).

Turns out you can play a secret chord on the keyboard and it pleases the system into issuing the necessary command to the drive to eject!
Hallelujah!

[Mr Larrington]

Isn't there a hole next to the slot for an unbent paper clip?

[Ham]

Made a mobile more child (and concerned parent) friendly by installing Children Tracker and AppLocker. The moral dilemma created by installing the former is still to be resolved.

Back in the day (when chat rooms/MSN were all the kiddie rage) I installed keyboard logging / website monitoring etc on Miss Ham's computer and checked it regularly. It was difficult on occasion not acting or reacting on the knowledge I had, but that wasn't why it was there. Screw the moral dilemma, you have a responsibility to look after kids. In the unlikely event that you needed it to be there and it wasn't, and you are technologically savvy to have done so, you would never forgive yourself. No dilemma, no option.

[tiermat]

Made a mobile more child (and concerned parent) friendly by installing Children Tracker and AppLocker. The moral dilemma created by installing the former is still to be resolved.

Back in the day (when chat rooms/MSN were all the kiddie rage) I installed keyboard logging / website monitoring etc on Miss Ham's computer and checked it regularly. It was difficult on occasion not acting or reacting on the knowledge I had, but that wasn't why it was there. Screw the moral dilemma, you have a responsibility to look after kids. In the unlikely event that you needed it to be there and it wasn't, and you are technologically savvy to have done so, you would never forgive yourself. No dilemma, no option.

Thank you, and the number of arguments about us checking her phone have dropped*, so a win all round.

*We don't need to have physical acess to the phone, as I can see everything from the web portal!  I have discovered, however that her chat conversation are really really boring!

[Phil W]

I've written web server code to read a gpx track and interpolate the 4 nearest elevation data points from the now free OS data. It also does an ascent calc using maxima and minks detection in the resulting heights.

I've written a web page to display a svg map of the UK and allow any gpx track you fire at it.

I've written some code to reduce the number of points in a gpx track to a set tolerance.

[hulver]

Fitted a new digitiser glass to the distinctly non-bouncy Asus tablet. That was a pain. Never done the glass before. Hair drier on hot, hotter, no - more heat. Pull the old surround off, lever the chips of broken glass that were left out of the glue. Clean the new glass, wear gloves so I don't get finger prints on the inside or the screen.

Re-assemble (so glad I took pictures as I dismantled the thing, they came in very handy).

Turn on. Computer part works, but touch screen is not working at all.

Re-check that the very small, very fiddly ribbon cables have been pushed in enough (they hadn't).

Turn it on again. Touch screen sort of works, but is all over the place. Reboot. Peal off the protective cover. Reboot again. Calibrate the screen, reboot, remove the calibration data, reboot again.

It works!

Snap the back cover back on.

Really happy that I've got it working again, but I think I need new eyes, everything was too small.

[tiermat]

Fitted a new digitiser glass to the distinctly non-bouncy Asus tablet. That was a pain. Never done the glass before. Hair drier on hot, hotter, no - more heat. Pull the old surround off, lever the chips of broken glass that were left out of the glue. Clean the new glass, wear gloves so I don't get finger prints on the inside or the screen.

Re-assemble (so glad I took pictures as I dismantled the thing, they came in very handy).

Turn on. Computer part works, but touch screen is not working at all.

Re-check that the very small, very fiddly ribbon cables have been pushed in enough (they hadn't).

Turn it on again. Touch screen sort of works, but is all over the place. Reboot. Peal off the protective cover. Reboot again. Calibrate the screen, reboot, remove the calibration data, reboot again.

It works!

Snap the back cover back on.

Really happy that I've got it working again, but I think I need new eyes, everything was too small.

Now you've done that, do you want to do Samsung Galxy S2 that had an unfortunate interface with a wall, not once, but three times?

[hulver]

Now you've done that, do you want to do Samsung Galxy S2 that had an unfortunate interface with a wall, not once, but three times?

Give it a go yourself, you can hardly make it worse!

There are front screen replacement kits on ebay for a tenner. Although I think after 3 visits against a wall, there might be more wrong with it than just the screen?

[tiermat]

Now you've done that, do you want to do Samsung Galxy S2 that had an unfortunate interface with a wall, not once, but three times?

Give it a go yourself, you can hardly make it worse!

There are front screen replacement kits on ebay for a tenner. Although I think after 3 visits against a wall, there might be more wrong with it than just the screen?

You would think so, wouldn't you? I connected it to a computer after the incident and could see the filesystem etc.

Obv. dunno if things like the radio still work, but do know that the glass is in LOTS of little pieces and the LCD is fubar'd.

[hulver]

You would think so, wouldn't you? I connected it to a computer after the incident and could see the filesystem etc.

Obv. dunno if things like the radio still work, but do know that the glass is in LOTS of little pieces and the LCD is fubar'd.

LCD as well? Might not be worth repairing then, as you can't tell what else is broken.

[Afasoas]

Tonight I commenced the not insubstantial task of implementing my home brew pfSense firewall. The trigger for this event was the procurement of a tellybox with smarts. I figured it would most probably be fertile territory for any would-be doers of evil and with the old tellybox out of the way I'd be able to get at the cheapBroadBeanProviderMagicSnuffBox that provides the loverly interwebs to his household.

For legacy's sake I've been running two networks up until now, so I've also taken the opportunity to set-up a wireless bridge as a stop gap making the two networks into one big problem.

I'm amazed it works. Particularly given that the DNS/DHCP server is on one end of the wireless bridge and the access point/firewall on t'other. There's no trolls beneath said bridge as yet. I look forward thobbut to replacing said rickety bridge with some of stan's most twisted copper strands.

[Kim]

I can vouch for M0n0wall (lean, mean relative of pfSense that actually supports IPv6) as something that Just Works.  An element of knowing what you're doing required to set it up, of course, but after that it's a happy little hamster spinning in its wheel.   

[Afasoas]

Hi Kim,

I'm inferring from your post that IPv6 isn't fully supported by pfSense? I've (for now) completely disabled IPv6 on my network as I've not got the same handle on it as I have on IPv4. I don't think the dsl modem or wireless access point actually support IPv6 anyway. ...Although I've got to get my head around it properly at some point

TBH I took the decision to use pfSense because that's what we use at work and I more or less know my way around it now.

[Kim]

Well, a few years ago when I was looking for a router/firewall that supported IPv6, pfSense was firmly in denial over the need for it.  A quick look suggests that substantial progress has been made since then, but I'm not sure how well integrated it is.

The access point shouldn't need to support it - it's just bridging the networks, and mine doesn't have IPv6 support either (though obviously you're stuck with an IPv4 management interface, that shouldn't usually be a problem).  Similarly the modem should be fine if it's doing PPPoE bridging, though not if it's the PPP endpoint itself.

It's a bit of a learning curve, mostly pertaining to the hodgepodge of RA/DHCPv6 required for full automagic configuration.  If your ISP and router support it, it's probably worth getting your head round it at some point, as there's only going to be more of it in the future.

[Chris S]

What even is the point of IPv6 on a LAN/Local WiFi? Surely there are enough addresses in IPv4 space for the local network, and IPv6 is more for global networking?

[Feanor]

Only if you have your LAN behind a NAT.

And ( All Together, Everyone! ): NAT is Evil.   It breaks proper end-to-end connectivity.

[Afasoas]

What even is the point of IPv6 on a LAN/Local WiFi? Surely there are enough addresses in IPv4 space for the local network, and IPv6 is more for global networking?

Using IPv6 on a local network eliminates the need for NAT. Which I think is the point Feanor was making.
And personally, I'd just want to learn about implementing it ahead of any plans to start hosting with IPv6 at work.

[Feanor]

Yes, it was.
A a simple example of why NAT is Evil, let's look at a scenario.

You have many devices in your house which have web interfaces.
IP webcams, PVRs, Weather Stations, Heating Controls, Fridges etc etc.

On your home LAN, all can be accessed directly.
All the devices are standard http servers on port 80.

But remotely?
You need to port-forward through your NAT to each device manually.
Each device must appear on a separate port on your external IP which will then map through to the device's port 80.

That's a clusterfuck.

You don't even need to be running servers to feel the pain.
Plenty of clients don't handle being behind NAT well either.
FTP and SIP come to mind.

[Feanor]

Ooh, and if you have full external IPv6 connectivity too, you also get to see the games they play with IPv6 addresses:

C:\Users\Ron.HOMENET>ping facebook.com

Pinging facebook.com [2a03:2880:2130:cf05:face:b00c:0:1] with 32 bytes of data:
Reply from 2a03:2880:2130:cf05:face:b00c:0:1: time=125ms
Reply from 2a03:2880:2130:cf05:face:b00c:0:1: time=124ms
Reply from 2a03:2880:2130:cf05:face:b00c:0:1: time=124ms
Reply from 2a03:2880:2130:cf05:face:b00c:0:1: time=125ms

Shit ping times, but look at the IP address!

[Feanor]

And see who can visit this website:

http://loopsofzen.co.uk/

Call your ISP if you can't.
It's on the Internet.   Why can't you get to it?
The reason is that it's IPv6 only:

C:\Users\Ron.HOMENET>nslookup
Default Server:  homenetdc03.homenet.local
Address:  2001:8b0:b7:1::3

> loopsofzen.co.uk
Server:  homenetdc03.homenet.local
Address:  2001:8b0:b7:1::3

Name:    loopsofzen.co.uk
Address:  2001:8b0:0:30::666:102


See, no A-record ( legacy IPv4 ).
Hassle your ISP.   They are supposed to be providing *Internet* access.
All of it.
Not just the old legacy IPv4 corner of the Internet.