[PLUG] it gets weirder - was Linux 7.2 printer problem solved

Michael Rasmussen rasmussenm at columbiafunds.com
Thu Mar 21 16:46:16 UTC 2002


I got curious about why the configuration of 192.168.200.081 doesn't work.
Poked around on the machine for a bit and found that `ifconfig
192.168.0.001` works as does `ifconfig 192.168.0.071` 

Then a bit of shell:

 for i in 6 7 8 9
 do    
   for j in 0 1 2 3 4 5 6 7 8 9
   do       
      ifconfig eth0 down
      echo trying 0$i$j >> conflog 
      ifconfig eth0 192.168.200.0$i$j >>conflog 2>&1
      echo trying $i$j >> conflog
      ifconfig eth0 192.168.200.$i$j >> conflog 2>&1
   done
 done

And the results show an error whenever a digit larger than 7 is in the
specified address:

 trying 067
 trying 67
 trying 068
 192.168.200.068: Unknown host
 ifconfig: '--help' gives usage information.
 ...
 trying 077
 trying 77
 trying 078
 192.168.200.078: Unknown host
 ifconfig: `--help' gives usage information.
 trying 78

So Robert, the real answer to your question is:

an IP address ending in .081 is invalid - because the leading 0 tells the
software to interpret the number in octal.  In octal only digits 0-7 are
valid.  For that matter and address of say 192.168.081.001 would also be
invalid. Because the 3rd octet is not a valid octal number.  

You could also try something like `ifconfig eth0 192.168.0x081.1` which
would result in an address of 192.168.129.1.

Thanks for the interesting problem.  

--  
  Michael Rasmussen - Network Engineer, Columbia Management
  voice:  971-925-6723  cell:  503-807-1447  rasmussenm at columbiafunds.com
  <mailto:rasmussenm at columbiafunds.com> http://www.columbiafunds.com

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