I have the following database that I want to use for logging network configutations:

CREATE TABLE ip (
    id INT NOT NULL AUTO_INCREMENT,
    address VARBINARY(16) NOT NULL,  -- IPv4 or IPv6
    PRIMARY KEY (id),
    UNIQUE (address)
);

CREATE TABLE mac (
    id INT NOT NULL AUTO_INCREMENT,
    address VARBINARY(100) NOT NULL,  -- hardware address (usually MAC)
    PRIMARY KEY (id),
    UNIQUE (address)
);

CREATE TABLE network (
    id INT NOT NULL,
    mac INT NOT NULL,
    ip INT NOT NULL,
    INDEX (id),
    FOREIGN KEY (mac) REFERENCES mac(id),
    FOREIGN KEY (ip) REFERENCES ip(id)
);

When logging a network configuration, I do not want any rows to be inserted if the network configuration (combination of MAC and IP addresses) already exists. In that case I just want to get the corresponding id from the network table. What is the best way to do this?