| 摘要 |
PROBLEM TO BE SOLVED: To provide a firewall which automatically decides permission and a refusal of communication by probing contents of SDP description corresponding to SIP / SDP, or an equivalent function. SOLUTION: The firewall is provided with; an INVITE method detection means which detects an INVITE method from a transmitted IP packet; an address and ID recording means which acquires a call ID from a SIP header of an IP packet in addition to the transmission source address and the transmission destination address from an IP header of the received IP packet, and records acquired transmission source address, a transmission destination address and a call ID on a table; and a port number recording means which acquires a port number to be used in future communications from SDP description which is contained in a response code transmitted from a receiving side responding to the INVITE method transmitted from the transmission source, and records acquired port number on a table. Thus, the firewall makes it possible to permit communication of only the port number with the acquired transmission source address and transmission destination address. COPYRIGHT: (C)2005,JPO&NCIPI
|
