Crossed Wires

Vic’s Blog

Posts Tagged fedora

What a difference a working resolver makes

Aug 7

Posted by Vic in Linux, Networks, Work | No Comments

The next phase in tidying up my user authentication environment in the lab was to enable SSL/TLS on the z/VM LDAP server I use for my Linux authentication (I’ll discuss the process on the DeveloperWorks blog, and put a link here).  Apart from being the right way to do things, LDAP authentication appears to require SSL or TLS in Fedora 15.

After I got the Fedora system working, I thought it would be a good idea to have other systems in the complex using SSL/TLS also.  The process was moderately painless on a SLES 10 system, but on the first SLES 11 system I went to YaST froze while saving the changes.  I (foolishly) rebooted the image, and it hung during boot.  Not fun.

After a couple of attempts to fix up what I thought were the obvious problems (each attempt involving logging off the guest, connecting its disk to another guest, mounting the filesystem, making a change, unmounting and disconnecting, and re-IPLing) with no success, I went into /etc/nsswitch.conf and turned off LDAP for everything I could find.  This finally allowed the guest to complete its boot — but I had no LDAP now.  I did a test using ldapsearch, which reported it couldn’t reach the LDAP server.  I tried to ping the LDAP server by address, which worked.  I tried to lookup the hostname of the LDAP server, and name resolution failed with the traditional “no servers could be reached” message.  This was odd, as I knew I’d changed it since it was pointing to the wrong DNS server before…  I could ping the DNS by address, and another system resolved fine.

I thought it might have been a configuration problem — I had earlier had trouble with systems not being able to do recursive DNS lookups through my DNS server.  I went to YaST to configure the DNS Server, and it told me that I had to install the package “bind”.  WHAT?!?!?  How did the BIND package get uninstalled from the system…

Unless…  It’s the wrong system…

I checked /etc/resolv.conf on a working system and sure enough I had the IP address wrong.  I was pointing at a server that was NOT my DNS server.  Presumably the inability to resolve the name of the LDAP server I was trying to reach is what made the first attempt to enable TLS for LDAP fail in YaST, and whatever preload magic SLES uses to enable LDAP authentication got broken by the failure.  Setting the right DNS and re-running the LDAP Client module in YaST not only got LDAP authentication working but got me a bootable system again.

A simple fix in the end, but I’d forgotten the power of the resolver to cause untold and unpredictable havoc.  Now, pardon me while I lie in wait for the YaST-haters who will no doubt come out and sledge me…  :-)

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Motion Computing Tablet PC

Aug 13

Posted by Vic in Hardware, Work | No Comments

Thanks to work, I am now the possessor of a rather cool piece of kit: a tablet PC. It’s a Mobile Computing LE1700, and I’m quite impressed with how it works. The big question though is of course… Will it run Linux?

At the moment it’s still running Windows XP Tablet Edition, but that’s only because a Hardy Heron install DVD is quite some way away from me right now.

I just trained Microsoft speech recognition and this paragraph has been dictated using speech recognition.  The recognition rate is actually quite good for the amount of training I’ve done, although I am having to go back and correct quite a few minor errors.

Back to handwriting recognition, which is outstanding: it’s only just now, as I write on the screen of this device, that I realise how poor my handwriting has become! Almost certainly this is due to lack of practice and under-use! I can tell as I’m writing that its recognition is somewhat dictionary-based, as if I pause or lift the pen it will make a guess abort what I’ve written which it will change as I complete the word.

Credit where credit is due, I think tablet Windows looks pretty good. Having used it before just putting Ubuntu on, I’ll be expecting a bit more from Linux…

On the hardware side, the machine looks quite sturdy and solid — so much so it’s a bit or the weighty side. I did install the additional battery pack though, and I’m sure that if I was adopting a proper tablet-PC posture it wouldn’t feel as heavy as it does. It has a 3G modem built-in, which works fine with my Telstra USIM (that’s how I’m posting this now), and the usual complement of Wi-Fi, Bluetooth, PC-Card, SD  and infra-red. It even has a place to stow the pen-stylus.

As I said, I don’t have a Linux disc handy to start setting up properly so the big Linux question will have to wait for a while. Some early Googling shows that there is support for most of the hardware components in it (the digitiser is Wacom, the Wi-Fi is Intel 3945, I’ve even seen support for the 3G adapter. It’s the interface and application level that I’m worried about — the state of handwriting recognition, whether XRandR lives up to the promise, and so on. I’ll post more as I get used to it and see what it can do…

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