Arduino

Reference Language | Libraries | Comparison | Changes

Ethernet

## Ethernet.begin()

#### Description

Initializes the ethernet library and network settings.

With version 1.0, the library supports DHCP. Using Ethernet.begin(mac) with the proper network setup, the Ethernet shield will automatically obtain an IP address. This increases the sketch size significantly. To make sure the DHCP lease is properly renewed when needed, be sure to call Ethernet.maintain() regularly.

#### Syntax

Ethernet.begin(mac);
Ethernet.begin(mac, ip);
Ethernet.begin(mac, ip, dns);
Ethernet.begin(mac, ip, dns, gateway);
Ethernet.begin(mac, ip, dns, gateway, subnet);

#### Parameters

mac: the MAC (Media access control) address for the device (array of 6 bytes). this is the Ethernet hardware address of your shield. Newer Arduino Ethernet Shields include a sticker with the device's MAC address. For older shields, choose your own.

ip: the IP address of the device (array of 4 bytes)

dns: the IP address of the DNS server (array of 4 bytes). optional: defaults to the device IP address with the last octet set to 1

gateway: the IP address of the network gateway (array of 4 bytes). optional: defaults to the device IP address with the last octet set to 1

subnet: the subnet mask of the network (array of 4 bytes). optional: defaults to 255.255.255.0

#### Returns

The DHCP version of this function, Ethernet.begin(mac), returns an int: 1 on a successful DHCP connection, 0 on failure. The other versions don't return anything.

#### Example

#include <SPI.h>
#include <Ethernet.h>
// the media access control (ethernet hardware) address for the shield:
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
//the IP address for the shield:
byte ip[] = { 10, 0, 0, 177 };
void setup()
{
Ethernet.begin(mac, ip);
}
void loop () {}
[Get Code]
Reference Home

Corrections, suggestions, and new documentation should be posted to the Forum.

The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.

### Share

### This link has expired.
Please re-subscribe to our Newsletters.

### Subscribe to our Newsletters

Email

Please enter a valid email to subscribe

Arduino Newsletter
Arduino Store Newsletter

### Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy

###### Newsletter

- ©2015 Arduino
- Copyright Notice
- Contact us
- About us
- Careers