System for performing remote operation between firewall-equipped networks or devices

A system which is provided with a servicing unit connected to a first internal network in which a first firewall is installed for an external network and a serviced unit connected to a second internal network in which a second firewall is installed for said external network, wherein said servicing unit performs a remote operation on said serviced unit through said external network, said serviced unit comprising:

• packet communications means for setting up a connection with said first firewall via said second firewall and transmitting packets to or from said first firewall over said connection;
• and
• security check means for checking remote operation directive information contained in packets received by said packet communications means for validity;
• remote operation execution means for performing a remote operation on said serviced unit as indicated by said remote operation directive information which has been validated by said security check means;
• and
• execution result return means for returning the result of execution of said remote operation by said remote operation execution means to said first firewall through said packet communications means.

A system which is provided with a servicing unit connected to a first internal network in which a first firewall is installed for the Internet and a serviced unit connected to a second internal network in which a second firewall is installed for said Internet, wherein said servicing unit performs a remote operation on said serviced unit through said Internet, said serviced unit comprising:

• packet communications means for setting up a connection with said first firewall via said second firewall and transmitting packets to or from said first firewall over said connection;
• and
• security check means for checking remote operation directive information contained in packets received by said packet communications means for validity;
• remote operation execution means for performing a remote operation on said serviced unit as indicated by said remote operation directive information which has been validated by said security check means;
• and
• execution result return means for returning the result of execution of said remote operation by said remote operation execution means to said first firewall through said packet communications means.

A central unit which functions as a second firewall against access to a servicing unit via an external network by a serviced unit connected to a first internal network in which a first firewall is installed for said external network, comprising:

• first packet communications means for setting up a first connection with said serviced unit via said first firewall and said external network and transmitting packets to or from said serviced unit over said first connection;
• security check means for determining whether or not packets received by said packet communications means after said first connection has been set up are packets transmitted from a serviced unit of a contract user;
• and
• second packet communications means for, when the determination by said security check means is that said packets are packets from said serviced unit of a contract user, setting up a second connection with said servicing unit via a second internal network connected to said central unit and transmitting packets to or from said servicing unit connected to said second internal network over said second connection.

A central unit which functions as a second firewall against access to a servicing unit via the Internet by a serviced unit connected to a first internal network in which a first firewall is installed for said Internet, comprising:

• first packet communications means for setting up a first connection with said serviced unit via said first firewall and said Internet and transmitting packets to or from said serviced unit over said first connection;
• security check means for determining whether or not packets received by said packet communications means after said first connection has been set up are packets transmitted from a serviced unit of a contract user;
• and
• second packet communications means for, when the determination by said security check means is that said packets are packets from said serviced unit of contract user, setting up a second connection with said servicing unit via a second internal network connected to said central unit and transmitting packets to or from said servicing unit connected to said second internal network over said second connection.

A unit to be serviced which is connected to a first internal network in which a first firewall is installed for an external network and receives a remote operation service from a servicing unit connected to a second internal network in which a second firewall is installed for the external network, comprising:

• packet communications means for establishing a connection to the second firewall through the first firewall, and transmitting a packet to and from the second firewall through the connection;
• security check means for checking security of remote operation directive information stored in the packet received by said packet communications means;
• remote operation execution means for performing a remote operation on the unit to be serviced according to the remote operation directive information whose security is checked by said security check means;
• and
• execution result return means for returning an execution result of the remote operation performed by said remote operation execution means to the second firewall through said packet communications means.