DHCP server (version 4) with an alias IP address

[Simon Hobson]

Steven Shiau wrote:

>Is that possible to use an alias IP address to run the DHCP service 4?

Yes.

>We have been used dhcp3 service with this method for a long time, 
>however, recently we switched to 4.1 or 4.2, and we hit an issue 
>that the dhcpd always complains "No subnet declaration for eth0 
>(...)"

Which is correct - you are missing a declaration for it. You need a 
shared network declaration, and a declaration for the other subnet :

shared-subnet "some-identifier" {
   subnet 192.168.100.0 netmask 255.255.255.0 {
     option subnet-mask  255.255.255.0;
     option routers 192.168.100.254;
     next-server 192.168.100.254;

     pool {
       range 192.168.100.1 192.168.100.3;
     }
   }
   subnet 192.168.120.0 netmask 255.255.255.0 {
   }
}

Note. In this case shared-network is correct because 192.168.100.0/24 
and 192.168.120.0/24 are both on the same broadcast domain. Not to be 
confused with VLANs etc.

-- 
Simon Hobson

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