---
title: "Wiznet W5100 UDP multicast Socket 0"
url: "https://maker.wiznet.io/forum/13035"
markdown_url: "https://maker.wiznet.io/forum/13035/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "mmprestine"
created: "2018-08-23T18:45:27+09:00"
last_activity: "2018-08-28T01:20:56+09:00"
language: "en"
views: 1024
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Wiznet W5100 UDP multicast Socket 0

## Question

Asked by mmprestine on 2018-08-23 in Ethernet Chips.

I have a test setup for socket 0 in multicast. I can receive multicast packets but cannot receive unicast packets on this socket.

Is it possible to receive multicast and unicast packets on socket 0 when configured for multicast?

Matt

## Replies

### Reply 1 by irina, 2018-08-28

Hi Matt,

Before set OPEN command on W5100 socket 0 command register, write the Multicasting group
address, Multicasting Hardware Address and port number to S0_DIPR(Destination IP Register),
S0_DHAR(Destination Hardware Address Register) and S0_DPORT(Destination Port Number
Register).

Please Download the link as below. Some of these files have in How to use Multicast document and firmware.
<https://www.wiznet.io/wp-content/uploads/wiznethome/Chip/W5100/Application%20Note/W5100_Application_Note.zip>

thanks,

---

Source: https://maker.wiznet.io/forum/13035