JPH11154966A - Inter-lan connection method and connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct inter-LAN connection through a proper path without having a solution system of an IP address in its own terminal or its own LAN. SOLUTION: An inter-LAN connection device 1a retains an IP address of a transfer destination DNS server 2b corresponding to a LAN terminal 2c. An IP address of the DNS server 2b corresponding to a connected LAN terminal 2c is retrieved on request of a LAN terminal 1c and the terminal connects with the DNS server 2b and an inquiry request of the IP address of the LAN terminal 2c is transferred to the DNS server 2b. An IP address of the LAN terminal 2c sent from the DNS server 2b is transferred to the LAN terminal 1c via the inter-LAN connection device 1a and the LAN terminal 1c starts the connection to the LAN terminal 2c by using the received IP address.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-LAN connection method and a connection apparatus for determining a connection path when connecting between LANs using a public line.

[0002]

2. Description of the Related Art Conventionally, when a plurality of LANs are connected using a LAN connection device using a public line, a connection destination is specified using a routing control table of an Internet protocol layer.

FIG. 6 shows a LAN (Local A) at another point.
FIG. 2 is a configuration diagram in a case where the network is connected using a public network. Normally, when the LAN terminal 1c in the LAN 1 tries to connect to the LAN terminal 2c in the LAN 2, the designation of the LAN terminal 2c includes IP (Inter).
net protocol) uses a host name instead of an address.

However, the existing route determination method is I
Since it is necessary to know the P address, the LAN terminal 1c
When connecting to the LAN terminal 2c, the LAN terminal 2c has a host name / IP address conversion table in its own terminal or the same LA.
A server having a function of converting a host name and an IP address is prepared in N, and the IP address of the LAN terminal 2c is obtained and connected to the LAN terminal 2c.

As a method of connecting to a partner LAN terminal, there is a method described in Japanese Patent Laid-Open No. 7-107120.

[0006]

In the conventional method described above, in the case of a method having a conversion table of a host name and an IP address in its own terminal, when the IP address of the destination LAN terminal is changed, The information had to be corrected by humans. Also, in the case of a method of preparing a server having a function of converting a host name and an IP address in one LAN, the change of the IP address is automatically updated. There was a problem that it occurred.

SUMMARY OF THE INVENTION An object of the present invention is to provide a route selection method for accurately connecting to a destination LAN terminal without holding a host name and IP address resolution system in its own terminal or its own LAN.

[0008]

According to the present invention, there is provided an inter-LAN connection method comprising the steps of:
The P-address is stored in the DNS server table of the own LAN connection device, and an inquiry request for conversion from the host name of the partner LAN terminal to the IP address is made to the own LAN connection device by the own LAN terminal. The inter-LAN connecting device searches the DNS server table for the IP address of the DNS server corresponding to the partner LAN terminal, connects to the DNS server, and receives the DNS address inquiry request from the own LAN terminal. To the server, and by the DNS server,
Transferring the IP address of the partner LAN terminal in response to the inquiry to the own LAN terminal via the own LAN connection device;
The own LAN terminal transmits an IP packet to the partner LAN terminal using the IP address.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a case where a LAN is connected to another point using the LAN connection method of the present invention.
In FIG. 1, an inter-LAN connecting apparatus 1a includes a domain name (Domain) in addition to normal routing control information in advance.
Destination DNS (Domain) corresponding to the
Name System) server information is stored in a table (hereinafter, referred to as a DNS server table).

FIG. 2 is a diagram showing the contents held in the DNS server table. In this table, a DNS server of a transfer destination is registered for each hierarchical structure of a formal host name defined in DNS. The LAN terminal 1c registers the IP address of the LAN connection device 1a as a DNS server to which the LAN terminal 1c refers.

When connecting to the LAN terminal 2c, the LAN terminal 1c sends an inquiry request for converting the host name of the LAN terminal 2c to an IP address.
Send to a. The LAN-to-LAN connecting device 1a searches for an appropriate connection path from the inquired host name, connects the line, and transfers the inquiry request to the registered destination DNS server after the line connection.

The DNS server having received the inquiry request sends a response to the inquiry to the LAN connection device 1a.
To return. The LAN connection device 1a transfers the response received from the DNS server to the LAN terminal 1c.

As a result, the LAN terminal 1c can perform LAN-to-LAN connection through an appropriate route without having an IP address resolution system in its own terminal or its own LAN.

FIG. 3 is a block diagram showing an embodiment of an inter-LAN connecting apparatus employing the inter-LAN connecting method of the present invention. In FIG. 3, an inter-LAN connection device includes a LAN communication control unit 41 for controlling data communication with a LAN, a public line communication control unit 42 for controlling connection / disconnection of a public line and data communication, and a route control unit. Data input control unit 43 for inputting appropriate data, and first route control unit 4 of the existing system
4 and a second path control unit 45 for realizing the LAN connection method of the present invention.

The second path control unit 45 is provided with the LA of the present invention.
Host name and DNS required to implement N-to-N connection method
The server's corresponding data is stored as a table.
This data is input by the user through the data input control unit 43. The first path control unit 44 performs path control using an existing IP address.

Next, the operation of the LAN connection apparatus shown in FIG. 3 will be described in detail with reference to FIGS.
FIG. 4 is a sequence diagram showing a signal flow between the LAN terminal 1c and the LAN terminal 2c.

A terminal belonging to each LAN always has an official host name including a domain name. First, the user of the LAN-to-LAN connecting device 1a inputs necessary route control data to the second route control unit 45 through the data input control unit 43. The route control data includes a domain name serving as a key for searching for a route and a DNS corresponding to the domain name.
Consists of the IP address of the server. Second path control unit 4
5 stores this data in a table as shown in FIG. The LAN terminal 1c registers the inter-LAN connecting device 1a in advance as a DNS server to which the LAN terminal 1c refers.

Next, the LAN terminal 1c connects to the remote LAN 2
When trying to connect to the LAN terminal 2c existing in
Since it is necessary to know the IP address from the host name of the AN terminal 2c, the LAN terminal 2c is sent to the inter-LAN connecting device 1a registered as a DNS server to which the user refers.
Is transmitted. This inquiry request includes the formal name of the LAN terminal 2c “LAN terminal 2c.LAN2.co.jp”.

From the LAN terminal 1c to the IP of the LAN terminal 2c
Upon receiving the address inquiry request, the inter-LAN connecting device 1a searches the DNS server table for the address of the DNS server corresponding to the LAN terminal 2c.

The search method will be described with reference to FIG. FIG. 5 is a flowchart for searching for the address of the DNS server. Upon receiving the DNS inquiry request from the LAN terminal 1c, the second path control unit 45 searches whether the host name included in the received inquiry request is included in the DNS server table. If no entry corresponding to the host name is found, set the host name to be searched to 1
Change to a higher domain name. That is, when the host name included in the inquiry request from the LAN terminal 1c is “LAN terminal 2c.LAN2.co.jp”, the search target is changed to “LAN2.co.jp” and this domain name is Perform a search with. This process is performed until an entry corresponding to the domain name is found from the table. If an entry is not found even after searching up to the top domain, the query request is ignored as an error.

In the case of this embodiment, the search succeeds because the DNS server for the LAN terminal 2c is registered as the DNS server 2b.

Next, the second route control unit 45 passes the address of the DNS server 2b included in the entry to the first route control unit 44 and sends the address to the LAN connection device 2a of the partner LAN where the DNS server exists. Make a connection to

After the connection between the LAN connection devices is completed, the LAN
The inter-connection device 1a transfers the IP address inquiry request received from the LAN terminal 1c to the DNS server 2b.

In the case of this embodiment, the DNS server 2
b can respond to the IP address inquiry request of the LAN terminal 2c,
This is transmitted to the inter-AN connection device 1a. LAN that received this
The inter-connection device 1a transfers the received IP address inquiry response to the LAN terminal 1c.

L knowing the IP address of LAN terminal 2c
The AN terminal 1c transmits an IP packet using the IP address. This packet is transferred to the LAN terminal 2 using the conventional route control method. At this time, LA
L in which the LAN terminal 2c exists in advance in the N connection process
Since the connection with the LAN connection device 2a of AN2 has been completed, there is no need to newly connect.

[0027]

As described above, according to the present invention, LA
This has the effect that the N terminal does not need to have means for resolving the IP address by itself. This allows home LAN
Etc. can be applied to a small LAN.

Further, according to the present invention, there is an effect that unnecessary connection does not occur. At the time of IP address inquiry, an appropriate connection partner is determined from the domain name of the inquiry address and connection to the partner LAN is performed. Therefore, when an IP packet is transmitted, the same connection destination as the connection partner determined by the existing routing method is used. Should be connected to

[Brief description of the drawings]

FIG. 1 is a configuration diagram when a LAN is connected to another point using the LAN connection method of the present invention.

FIG. 2 is a diagram showing contents stored in a DNS server table.

FIG. 3 is a configuration diagram illustrating an embodiment of an inter-LAN connection device.

FIG. 4 is a sequence diagram showing a signal flow between LAN terminals.

FIG. 5 is a flowchart for searching for an address of a DNS server.

FIG. 6 is a configuration diagram when a plurality of LANs are connected via a public network using a conventional method.

[Explanation of symbols]

1, 2, 3 LAN 1a, 1d, 2a, 2d, 3a, 3d Inter-LAN connecting device 1b, 2b, 3b DNS server 1c, 2c, 3c LAN terminal 41 LAN communication control unit 42 Training line communication control unit 43 Data input control Unit 44 first route control unit 45 second route control unit

Claims (7)

[Claims] 1. The connection information of a transfer destination DNS server corresponding to a partner LAN terminal is held in a connection device between own LANs, and connection information of a DNS server corresponding to a partner LAN terminal to be connected is requested by the own LAN terminal. And connects to the DNS server, and sends a query request for connection information of the partner LAN terminal to the DNS server.
The connection information of the partner LAN terminal sent from the DNS server is transferred to the own LAN terminal via the connection device between the own LANs, and the own LAN terminal uses the received connection information. Partner LA
A connection method between LANs, which starts connection with N terminals. 2. An IP address of a transfer destination DNS server corresponding to a host name is stored in a DNS server table of a connection device between own LANs.
An inquiry request for conversion to a P address
The connection is performed to the AN connection device, and the own LAN connection device searches the DNS server table for the IP address of the DNS server corresponding to the partner LAN terminal and connects to the DNS server by the own LAN connection device. An IP address inquiry request is transferred to the DNS server. The DNS server transfers the IP address of the partner LAN terminal to the inquiry to the own LAN terminal via the own LAN connecting device, and the own LAN terminal An inter-LAN connection method, wherein an IP packet is transmitted to the partner LAN terminal using an IP address. 3. The DNS server table according to claim 2, wherein an IP address of a transfer destination DNS server is stored for each hierarchical structure of a formal host name defined in DNS. LAN connection method. 4. When the host name cannot be searched,
4. The inter-LAN connection method according to claim 3, wherein the host name to be searched is changed to a domain name raised by one level. 5. A LAN communication control unit for controlling data communication with a LAN, a public line communication control unit for controlling connection / disconnection of a public line and data communication, and a data input control for inputting data necessary for path control. And a first path control unit for performing path control using an existing IP address, the IP address of the transfer destination DNS server corresponding to the host name is held as a DNS server table, and In response to a request for an IP address of the partner LAN terminal from the LAN terminal, an IP address of a DNS server corresponding to the partner LAN terminal is searched from the DNS server table, and the searched IP address is referred to as the first path control unit. To the DNS server after the connection with the DNS server is completed.
An inter-LAN connection device further comprising a second route control unit for transferring an IP address of the partner LAN terminal in response to an inquiry sent from an NS server to the own LAN terminal. 6. The DNS server table according to claim 5, wherein the DNS server table holds an IP address of a DNS server of a transfer destination for each hierarchical structure of an official host name defined in DNS. LAN connection device. 7. When the host name cannot be searched,
7. The inter-LAN connection apparatus according to claim 6, wherein the host name to be searched is changed to a domain name raised by one level.