net.BlockList

The BlockList object can be used with some network APIs to specify rules for disabling inbound or outbound access to specific IP addresses, IP ranges, or IP subnets.

blockList.addAddress(address, type?): void

Adds a rule to block the given IP address.

blockList.addAddresses(addresses, type?): void

Adds multiple address rules to the block list in a single operation. This is more efficient than calling blockList.addAddress() repeatedly when adding a large number of individual addresses, as the addresses are inserted under a single internal lock acquisition.

blockList.addCIDR(cidr): void

Adds a subnet rule using CIDR notation. The address family is automatically detected from the address (IPv6 if the address contains ':', IPv4 otherwise). This is equivalent to calling blockList.addSubnet() with the parsed network address, prefix length, and family.

blockList.addCIDRs(cidrs): void

Adds multiple subnet rules using CIDR notation in a single call. The address family for each entry is automatically detected. This is equivalent to calling blockList.addCIDR() for each element of the array.

blockList.addRange(start, end, type?): void

Adds a rule to block a range of IP addresses from start (inclusive) to end (inclusive).

blockList.addSubnet(net, prefix, type?): void

Adds a rule to block a range of IP addresses specified as a subnet mask.

blockList.check(address, type?): boolean

Returns true if the given IP address matches any of the rules added to the BlockList.

const blockList = new net.BlockList();
blockList.addAddress('123.123.123.123');
blockList.addRange('10.0.0.1', '10.0.0.10');
blockList.addSubnet('8592:757c:efae:4e45::', 64, 'ipv6');

console.log(blockList.check('123.123.123.123'));  // Prints: true
console.log(blockList.check('10.0.0.3'));  // Prints: true
console.log(blockList.check('222.111.111.222'));  // Prints: false

// IPv6 notation for IPv4 addresses works:
console.log(blockList.check('::ffff:7b7b:7b7b', 'ipv6')); // Prints: true
console.log(blockList.check('::ffff:123.123.123.123', 'ipv6')); // Prints: true

blockList.clear(): void

Clears all rules from the BlockList.

blockList.fromJSON(value): void

const blockList = new net.BlockList();
const data = [
  'Subnet: IPv4 192.168.1.0/24',
  'Address: IPv4 10.0.0.5',
  'Range: IPv4 192.168.2.1-192.168.2.10',
  'Range: IPv4 10.0.0.1-10.0.0.10',
];
blockList.fromJSON(data);
blockList.fromJSON(JSON.stringify(data));

• value Blocklist.rules

BlockList.isBlockList(value): void

A frozen array of CIDR strings representing private, loopback, and link-local IP address ranges. This can be passed to blockList.addCIDRs() to quickly populate a blocklist with all non-routable address ranges.

The included ranges are:

• 10.0.0.0/8 — RFC 1918 private IPv4
• 172.16.0.0/12 — RFC 1918 private IPv4
• 192.168.0.0/16 — RFC 1918 private IPv4
• 127.0.0.0/8 — IPv4 loopback
• ::1/128 — IPv6 loopback
• 169.254.0.0/16 — IPv4 link-local
• fe80::/10 — IPv6 link-local
• fc00::/7 — IPv6 unique local (ULA)

const blockList = new net.BlockList();
blockList.addCIDRs(net.BlockList.PRIVATE_RANGES);

console.log(blockList.check('10.0.0.1'));      // Prints: true
console.log(blockList.check('127.0.0.1'));     // Prints: true
console.log(blockList.check('8.8.8.8'));       // Prints: false

blockList.removeAddress(address, type?): void

Removes a rule that was previously added with blockList.addAddress(). The address must match exactly the value used when the rule was added. If the specified address does not exist, this is a no-op.

blockList.removeCIDR(cidr): void

Removes a subnet rule using CIDR notation. The address family is automatically detected from the address. This is equivalent to calling blockList.removeSubnet() with the parsed network address, prefix length, and family. If the specified subnet does not exist, this is a no-op.

blockList.removeRange(start, end, type?): void

Removes a rule that was previously added with blockList.addRange(). The start and end addresses must match exactly the values used when the rule was added. If the specified range does not exist, this is a no-op.

blockList.removeSubnet(net, prefix, type?): void

Removes a rule that was previously added with blockList.addSubnet(). The network address and prefix must match exactly the values used when the rule was added. If the specified subnet does not exist, this is a no-op.

The list of rules added to the blocklist.

The number of rules in the blocklist. This is equivalent to blockList.rules.length but does not allocate the rules array.

blockList.toJSON(): void