IPAddress Reservation (Best Practice)

[Simon Hobson]

Luis Fernando Lacayo wrote:
>Thank for the quick response...
>
>You are correct, I meant "Fixed address assignments"... That is what 
>I get from hanging around windows people.

Yeah, I try and avoid it ;-)

>>  >   my question is about how to define these reservations.  currently
>>>I have each reservation under its own subnet.  I have seen some
>>>configuration files that just bundles them at the end of the file.
>>>I imagine that this works.
>>
>>They MUST NOT be within a subnet declaration. With a few exceptions
>>for some rather unusual requirements, you REALLY do not want them in
>>your subnet declarations. Host statements are global in scope (and so
>>are still 'valid' when the client is not in that subnet - BUT,
>>clients matching a host statement will inherit some options from the
>>subnet where the host declaration is made.
>>
>OK, I think I understand.  Will this apply to the failover 
>configuration as well? 
>
>So this setup would be incorrect:
>
>## Third Floor South Wired
>subnet 10.129.76.0 netmask 255.255.254.0 {
>   option routers 10.129.76.1;
>   ...
>   option broadcast-address 10.129.77.255;
>   option domain-name-servers 10.129.161.20, 10.128.5.28;
>   option subnet-mask 255.255.254.0;
>   ......
>   pool {
>     failover peer "co-wan03";
>     deny dynamic bootp clients;
>     allow unknown-clients;
>     range 10.129.76.21 10.129.76.230;
>     range 10.129.77.21 10.129.77.230;
>   }
>
>   ## Anthony James
>   host Host-10.129.76.225 {
>     hardware ethernet 00:0d:56:a0:67:c4;
>     fixed-address 10.129.76.225;
>   }
>}
>
>## Fourth Floor Wired
>
>subnet 10.129.78.0 netmask 255.255.254.0 {
>   option routers 10.129.78.1;
>   ...
>   option broadcast-address 10.129.79.255;
>   option domain-name-servers 10.129.161.20, 10.128.5.28;
>   option subnet-mask 255.255.254.0;
>   ....
>   pool {
>     failover peer "co-wan03";
>     deny dynamic bootp clients;
>     allow unknown-clients;
>     range 10.129.78.21 10.129.78.230;
>     range 10.129.79.21 10.129.79.230;
>   }
>
>   host Host-10.129.78.232 {
>     hardware ethernet 00:20:6b:51:db:45;
>     fixed-address 10.129.78.232;
>   }
>
>
>It should be:
>
>## Third Floor South Wired
>subnet 10.129.76.0 netmask 255.255.254.0 {
>   option routers 10.129.76.1;
>   ...
>   option broadcast-address 10.129.77.255;
>   option domain-name-servers 10.129.161.20, 10.128.5.28;
>   option subnet-mask 255.255.254.0;
>   ......
>   pool {
>     failover peer "co-wan03";
>     deny dynamic bootp clients;
>     allow unknown-clients;
>     range 10.129.76.21 10.129.76.230;
>     range 10.129.77.21 10.129.77.230;
>   }
>}
>
>## Fourth Floor Wired
>
>subnet 10.129.78.0 netmask 255.255.254.0 {
>   option routers 10.129.78.1;
>   ...
>   option broadcast-address 10.129.79.255;
>   option domain-name-servers 10.129.161.20, 10.128.5.28;
>   option subnet-mask 255.255.254.0;
>   ....
>   pool {
>     failover peer "co-wan03";
>     deny dynamic bootp clients;
>     allow unknown-clients;
>     range 10.129.78.21 10.129.78.230;
>     range 10.129.79.21 10.129.79.230;
>   }
>}
>
>
>## Anthony James
>host Host-10.129.76.225 {
>   hardware ethernet 00:0d:56:a0:67:c4;
>   fixed-address 10.129.76.225;
>}
>
>## James Brown
>host Host-10.129.78.232 {
>   hardware ethernet 00:20:6b:51:db:45;
>   fixed-address 10.129.78.232;
>}


Yep, that's the difference.

>>  >How are you defining your reservations? and better yet how are you
>>>managing them?
>>
>>Many people store the information in a database (it can be anything
>>you are comfortable with), and then have a routine that will extract
>>the data and build a config file. You only need to build parts of a
>>file - for example you can just build a file with host declarations
>>and use the 'include" statement to include it in the main config file.
>>
>
>Any special program (Open source) that you recommend?

I think most people roll their own to suit their own needs. The only 
one that comes to mind is NetReg, but that solves a different issue 
(managing registration of known devices on a University campus) and I 
don't know if it can do anything like what you need.