|Windows WebDav SNI||Sunday 9th June 2013|
You can run multiple web-sites off of one host using virtual hosting. When your client (e.g. a browser) contacts the web-site, it sends the host name (e.g. www.aligrant.com) as part of the request, and the server can identify which site you want and not one of the others hosted on the same server.|
When it comes to secure web-sites that use SSL/TLS the request for the web-site is done after the secure connection is made. The snag here is that the name of the web-site must match the certificate for the SSL connection - but as the name of the site hasn't been sent it cannot do this.
Of course, this has been thought about and there is a standard to resolve this (RFC 4366). This works in a similar way as above, the name of the site you're interested in connecting to is sent as part of the secure connection setup. Problem solved. Pretty much every browser and client I've tried seems to support this.
Apart of course, for Windows WebDav client. The webdav client for Windows is pretty poor; this is yet another thing it doesn't support. You won't get any useful nor consistent error in return either. In order to support Windows you need to make sure your WebDav host is on the default host - i.e. if just the IP address of the server is entered, the certificate for your webdav server is returned and not any other virtual hosts instead.
|Monitor - finally?||Saturday 8th June 2013|
I think I have finally got a monitor that satisfies my loss of a CRT screen.|
This was released during the tail end of 2012 but has only just come to my attention. In a roundabout way, from a review of the 27" version. The highlights are:
- Real 8-bit display
- IPS panel
- Low input-lag
- LED backlight
- Matte & Glossy screen
There is a minimal edge to the monitor with the glass sitting over the edge of the display to create a smart look. It has a matte screen - but wonderfully, this is just a sticker that can be removed. As it happens, it's really very light and I haven't actually found the need to remove it (I think this is a one way decision).
It is only 16:9 and not 16:10, which would have been ideal, so not quite perfect. I think the resolution works slightly better than a 22" monitor for Full HD. The IPS display means that the viewing angles are good, and colours are constant across the entire screen.
The only thing missing from my impossible list of requirements is 75Hz as this display, and seemingly all other IPS displays, is rated at 60Hz. But - it can be driven past this with custom timings and will happily run at 72Hz, I haven't tried any higher yet.
I am so smitten, I may have to buy two.
|Linux dhclient not registering IPv6 hostnames||Sunday 2nd June 2013|
I am not sure if this is a recent thing, but my openSUSE 12.3 boxes were not registering their hostnames in DNS. I, as many only allow the DHCP server to update DNS. The idea is that the client includes it's name in the initial DHCP request.|
Whilst this works for IPv4 addresses, IPv6 wasn't.
The ISC dhclient program is what handles IPv6 DHCP (which is optional as IPv6 can auto configure). In openSUSE, YaST allows you to define the hostname to send to DHCP - but for some reason this doesn't work with IPv6. To fix it I manually updated the /etc/dhclient6.conf file with the line:
send fqdn.fqdn [hostname]. Whilst this field can accept the entire fully qualified domain, it is also allowed to just be the hostname. Using just the hostname allowed my DHCP server to assign the appropriate domain name.
I also had to delete the file /var/lib/dhcp6/dhclient6.eth0.lease file, which holds details of the last IPv6 address given to the device. Otherwise dhclient was only confirming it's address and not requesting one. Without requesting one the hostname wasn't being sent.
|Linux service status hanging||Saturday 1st June 2013|
You can check to see what the status of a service/daemon is in openSUSE linux by typing "rc**** status", replacing the stars with the service you're interested in. e.g. "rcapache2 status" to get Apache's status.|
Some gumph then gets outputted telling you whether it is running or not. And that should be the end of it.
On one of my servers this process wasn't completing. Whilst all the gumph was being outputting, the process didn't end.
There are different methods of managing services, openSUSE currently uses systemd. After some conversation with those in the know on their IRC channel, it was suggested to me that it might be the journal waiting to pass.
The journal is just a big log, allowed to grow to 10% of your disk unchecked. The server in question had a 1.4GB journal, and it is running on slow disks. A likely suspect. As it is just logging information, unless you have any need for it, it is safe to delete in a fit of rage.
The journal will log to /var/log/journal/ - you can clear out this directory without fear of failure.
To avoid this from happening again in the future you can also set up the configuration files not to use persistent storage.
Do this by changing the "Storage" entry in your /etc/systemd/journald.conf file to be "Storage=volatile".
This will instead make the logs go to /run/log/journal, and will not be maintained across reboots. There are some other options in the journald.conf file that allows you to put limits on space etc.