Automatic address assignment apparatus, control method, and program

Abstract

When an automatic address assignment apparatus is operating in a network, another automatic address assignment apparatus stops the automatic address assignment service thereof. When a wireless LAN access point which functions as an automatic address assignment apparatus (DHCP server device) sends a DHCP discover message on the network and a DHCP offer message is returned as a response therefor, and when the address of the transmission source of the DHCP offer message does not match the IP address thereof, it is determined that another DHCP server exists on the network, and the DHCP server service of the former DHCP server is stopped. Thus, by avoiding contention with another DHCP server and by preventing confusion of the network, a wireless LAN access point suitable, in particular, for use in a small-scale office or a home network managed by an ordinary user having no knowledge of IP can be formed.

What is claimed is:  
     
         1 . An automatic address assignment apparatus for lending an address to a client apparatus connected to a network, said automatic address assignment apparatus comprising: 
 sending means for sending search information for searching for an automatic address assignment apparatus in said network;    first determination means for determining whether or not predetermined information is transmitted from an automatic address assignment apparatus which exists on said network in response to the sending of said search information;    second determination means for determining whether or not the address of the transmission source of said predetermined information differs from the address of itself; and    stopping means for stopping the automatic address assignment service if the automatic address assignment service of itself is in the middle of being started when the determination result of said second determination means is yes.    
     
     
         2 . An automatic address assignment apparatus according to  claim 1 , wherein said automatic address assignment apparatus is a DHCP server device, said sending means sends a DHCP discover message on said network, said first determination means determines whether or not a DHCP offer message is received in response to the sending of said DHCP discover message, said second determination means determines whether or not the address of the transmission source of said DHCP offer message differs from the IP address thereof when the determination result of said first determination means is yes, and said stopping means stops the DHCP server service if the DHCP server service of itself in the middle of being started when the determination result of said second determination means is yes.  
     
     
         3 . A method of controlling an automatic address assignment apparatus for lending an IP address to a DHCP client connected to a network, said method comprising: 
 a first step of sending a DHCP discover message on said network;    a second step of determining whether or not a DHCP offer message is received in response to the sending of said DHCP discover message;    a third step of determining whether or not the address of the transmission source of said DHCP offer message differs from the IP address of itself when the determination result of said second step is yes; and    a fourth step of stopping an automatic address assignment service if the DHCP server service of itself is in the middle of being started when the determination result of said third determination result is yes.    
     
     
         4 . A program for causing a computer to perform a predetermined processing function, said program comprising: 
 a first step of sending a DHCP discover message on a network;    a second step of determining whether or not a DHCP offer message is received in response to the sending of said DHCP discover message;    a third step of determining whether or not the address of the transmission source of said DHCP offer message differs from the IP address of itself when the determination result of said second step is yes; and    a fourth step of stopping an automatic address assignment service if the DHCP server service of itself is in the middle of being started when the determination result of said third determination result is yes.