Networking

Overview

PeterOS uses a IP like system

Setup

Local setup

To set up a computer to access an existing network insure the computer has modem connected to the network (ie. ender modem to connect to wireless global network). Then run net.init() to connect and request and IP address. net.init() is called automatically by most programs that use the net package.

Once the computer has received an IP address from a DHCP server on the network, it can then talk to any other computer on the network via the receiver's IP address.

Global Network Setup

1) Network type

There are 2 types of global networks, wired, and wireless.

• Wireless global networks can be connected to without having to run new cabling to every computer or subnet, but requires ender modems.
• Wired networks on the other hand require a cable run to every computer, and prevents usage of pocket computers on the global network.

2) DHCP Server

For either type of network you need a Dynamic Host Configuration Protocol (DHCP) server.

In the default networking package there is a DHCP/DNS (Domain Name Service) server that can be used, found at /os/net/dhcp.lua. It can be used for both global networks and subnets, depending on configurations.

3) DHCP Config

The configuration file for the DHCP will be created at /home/dhcp.cfg and starts as the following

{
    "mask": 4294901760,
    "baseAddr": 3232235520,
    "addr": 3232235520,
    "addrTbl": {
        "defGateway": 3232235521,
        "dns": 3232235520,
    },
    "global": false,
    "adminPass": "admin"
}

See here for details

For global networks the config need to change to represent the global address space (0.0.0.0/8).

• mask needs to be set to 16777215 (0x00ffffff - 0.255.255.255)
• baseAddr, addr, and dns need to be set to 0 (0x000000 - 0.0.0.0)
• global needs to be set to true

In addition, it is recommend to change adminPass, as everyone may have access to the network, and could try the default password to maliciously set DNS records.

4) Adding DNS records

Once the network is up and running, you can domain name records to the server by going to 0.0.0.0 in a browser and entering the admin password set in the config. Then navigate to the DNS page, and click the Add Record button. The fields are:

• Name: Record hostname, ie. xyz.com
• Host: IP address of computer hostname should be directed to
• Port: Port filter for DNS record, defaults to any port if left empty (Advisory only)

Records can be edited by creating a new record with the same hostname.

Subnet Setup

1) Network type

Generally, subnets can only be wired, however, if the global networks is wired you can have a wireless subnet. Each subnet can only be wire or wireless, but you could have a subnet within you subnet that was wireless.

2) NAT Setup

If the subnet should be connected to the global network, you need to have a Network Address Transversal (NAT) device between the subnet and global network (or higher level subnet).

In the default networking package there is a NAT server that can be used, found at /os/net/nat.lua.

3) NAT Config

The configuration file for the NAT will be created at /home/nat.cfg and starts as the following

{
    "inside": {
        "side": "right",
        "mask": 4294901760,
        "baseAddr": 3232235520,
        "addr": 3232235521
    },
    "outside": {
        "side": "left"
    }
}

See here for details

If your subnet is not 192.168.0.0/16 then you need to change mask, baseAddr, and addr appropriately. See the Reserved IP Addresses IPV4 table for private network address ranges.

Important

addr is the LOCAL address of the NAT, it will get it's global address from a global DHCP.

Note

If you are using multiple layers of subnets, make sure their address spaces don't overlap to avoid communication issues.

4) DHCP Server

In addition to the NAT you need a Dynamic Host Configuration Protocol (DHCP) server.

In the default networking package there is a DHCP/DNS (Domain Name Service) server that can be used, found at /os/net/dhcp.lua. It can be used for both global networks and subnets, depending on configurations.

5) DHCP Config

The configuration file for the DHCP will be created at /home/dhcp.cfg and starts as the following

{
    "mask": 4294901760,
    "baseAddr": 3232235520,
    "addr": 3232235520,
    "addrTbl": {
        "defGateway": 3232235521,
        "dns": 3232235520,
    },
    "global": false,
    "adminPass": "admin"
}

See here for details

If you are not using the default subnet address space of 192.168.0.0/16, you need to update the config.

• mask is the subnet mask, ie. for a subnet of 10.0.0.0/8 the mask would be would be 4278190080 (0xff000000 - 255.0.0.0)
• baseAddr, addr, and dns need to be set to the base address of the subnet (ie. 10.0.0.0 for subnet 10.0.0.0/8)
• defGateway needs to be set the the LOCAL address of the NAT (usually one higher than dns)

In addition, it is recommend to change adminPass, as anyone with access to the network could try the default password to maliciously set DNS records.

6) Adding DNS records

Once the network is up and running, you can domain name records to the server by going to the base address (ie. 192.168.0.0) in a browser and entering the admin password set in the config. Then navigate to the DNS page, and click the Add Record button. The fields are:

• Name: Record hostname, ie. xyz.com
• Host: IP address of computer hostname should be directed to
• Port: Port filter for DNS record, defaults to any port if left empty (Advisory only)

Records can be edited by creating a new record with the same hostname.

Tip

DNS records will automatically be created on non-global networks if computers report a hostname when getting their IP address, with a .lan appended.

Advanced

IP Addresses

IP address under IPV4 (the scheme that PeterOS uses) are made up of 4 octets (groups of 8 bits, or 2 hex digest) witch represent both the host and subnet address of the computer. IP addresses are often written as 4 numbers speared by periods such as 192.168.0.0, however the save address can be written in hex as 0xc0a80000 or 3232235520 in combined decimal.

For technical reasons, many aspects of the networking packages store IP addresses as combined decimal numbers. However, there are functions in the package to easily interchange between formats: net.ipFormat(ip) turns a numeric IP address into an IPV4 address string, and net.ipToNumber(ip) turns an IPV4 string to a numeric address.

Address spaces

Every network has an address space, often written as x.x.x.x/y, where x.x.x.x is the base address, and y indicates the number of bits in the host portion of the IP address.

For example 192.168.0.0/16 indicates that the base address is 192.168.0.0 with a subnet mask of 255.255.0.0. This means that the last 2 octets of the IP address are used for assigning addresses in the address space (192.168.0.0 - 192.168.255.255), although the highest address is reserved for broadcast (also address -1 for PeterOS)

Some address spaces are reserved for specific purposes, see the Reserved IP Addresses IPV4 table for specifics.

Network Address Transversal (NAT)

Network Address Transferal allows messages to pass between different networks. It works by passing messages out and assigning a connection ID to outgoing messages and changing the origin address to the external address of the NAT. Then, when a reply comes back, the NAT can change the destination address based on the connection ID linking it to the original sender.

Because of this, messages can only come back in as reply to an outgoing message. In order to have message come in without having to be a response, you need a forwarding rule

Forwarding rules

NAT forwarding rules give an internal destination for messages matching a filter.

The default NAT has 2 filters for forwarding rules: domain and port.

• Domain will only forward any message that indicates it is destined for the specified domain name. (use * for any domain)
• Port will only forward messages on the specified port. (use * for any port)

For example:

Forward all RTTP messages for xyz.com to 192.168.2.27 with a rule looking something like:

{"domain":"xyz.com", "port":10080, "dest":"192.168.2.27"}

Forward all messages for xyz.com to server.lan with a rule looking something like:

{"domain":"xyz.com", "port":"*", "hostname":"server.lan"}

Forward all messages on port 10021 to server.lan with a rule looking something like:

{"domain":"*", "port":10021, "hostname":"server.lan"}