DHCPd Chatter Box!

Recently I was recovering from a major network failure after a prolonged power outage.  After reviving my lifeless and crippled network, there was no successful DHCP offers.  I noticed in my logs (/var/log/messages) the DHCP server was going crazy!

Unable to solve the issue, no systems getting an IP address despite the many many DHCPOFFERS, I caved, and built a new DHCP server as the weekend was ending and I just had to make this work.  An hour passes and the new dhcpd server is on its feet and machines are getting address.  However this new server is generating the same log hyperactivity.  But its working.  So I left it at that.

Here is a snippet from the /var/log/messages.  (MAC Addresses and hostnames have been changed for security reasons).


Oct 31 08:17:43 beardedlady dhcpd: DHCPREQUEST for 192.168.111.31 (192.168.1.11) from d4:20:6d:7e:4c:e0 (Android_) via eth0
Oct 31 08:17:43 beardedlady dhcpd: DHCPACK on 192.168.111.31 to d4:20:6d:e2:8b:e0 (Android_) via eth0
Oct 31 08:17:44 beardedlady dhcpd: DHCPDISCOVER from 00:24:36:ae:23:8b via eth0
Oct 31 08:17:45 beardedlady dhcpd: DHCPOFFER on 192.168.111.175 to 00:24:36:ee:74:8b via eth0
Oct 31 08:17:46 beardedlady dhcpd: DHCPREQUEST for 192.168.111.175 (192.168.1.11) from 00:67:36:ae:74:8b via eth0
Oct 31 08:17:46 beardedlady dhcpd: DHCPACK on 192.168.111.175 to 00:24:65:ae:74:8b via eth0
Oct 31 08:18:28 beardedlady dhcpd: DHCPREQUEST for 192.168.111.107 from 00:1a:ee:d5:85:ed (changedname) via eth0
Oct 31 08:18:28 beardedlady dhcpd: DHCPACK on 192.168.111.107 to 00:3d:e9:d5:85:ed (changedname) via eth0
Oct 31 08:18:57 beardedlady dhcpd: DHCPREQUEST for 192.168.111.200 from 00:21:70:ee:3f:81 via eth0
Oct 31 08:18:57 beardedlady dhcpd: DHCPACK on 192.168.111.200 to 00:21:ae:46:7f:81 via eth0
...

Fast forward a few hours, now Monday morning and people arriving and I have a pocket of my network down.  Not getting DHCP offers.  The "pocket of systems" gave me an indication as to what may be happening...   So I tried something as a last resort, and something that I should have tried first thing in retrospect.

I rebooted my network switches.  It seems the power issues caused one or more to go unstable.  The log settled right down, and dhcp requests and offers were all perfect.  So what solved this issue was to reboot my switches!

Android Paradigm and Task Killers

I just wanted to add a very quick post here.   This will not be long and only has one message.  Task Killers on Android are not necessary!  They are useful only if you want to "restart" an application.  Even that you can do in the native OS, via Manage Applications in your settings.  There will be a force stop under each application listed.

Android is excellent at managing applications and memory.  Here is how so called task killers reduce your performance.  When you have used an app and gone into others, android "suspends" the application.  Therefore when you later go back to that application, it beings it to the front.  Sort of like swapping.  But if you kill the applications, when you start them, you will be counter intuitive in the following ways:

• Your program has restarted rather than continuing from where you left off
• Takes longer to go back to a killed app as the system has to setup the environment and load all the program files again.  I cannot confirm this, but it follows to me that you would also use more battery, although small.  But hey!  Why waste?
• This one may sound a bit off, but hear me out.  You are not working in the Android paradigm.  What I mean here, is the idea is your apps are in a state where you left them.  Each app works in a "compartment".  When you switch to another, you just put that compartment down and use another.  Thus things are more easily "at your finger tips"  HA HA HA finger tips... ok.  But I hope you get my point here.

What I am trying to say here is Android is awesome at memory management.  By using task killers, you are counteracting part of what makes Android, well,.... Android.  :P   I suppose a task killer MAY be good for legacy droid devices where memory was a premium... but on any modern devices, task killers are just a problem.

Have a super-droid day!

//Ian\\