---
title: "WIZ5500 to have 1 socket as a TCP server & 2nd socket as a TCP client and have them connect & talk"
url: "https://maker.wiznet.io/forum/15927"
markdown_url: "https://maker.wiznet.io/forum/15927/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "dfarris1973"
created: "2025-11-07T00:06:52+09:00"
last_activity: "2025-11-07T13:28:00+09:00"
language: "en"
tags: ["W5500"]
views: 5
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# WIZ5500 to have 1 socket as a TCP server & 2nd socket as a TCP client and have them connect & talk

## Question

Asked by dfarris1973 on 2025-11-07 in Ethernet Chips.

I attempted to setup a WIZ5500 to have one socket as a TCP server and another socket as a TCP client and then attempted to have the client socket connect to the server socket, but can't get it to work. I can connect to the server socket with a client on my laptop and can connect to a server on my laptop from the client socket. Attempting to do this for unit testing so that the unit test is more automated, but can't seem to get it to work. Searches on google indicate this can be done on a WIZ5500, but I'm skeptical. Can anyone confirm this can be done on a WIZ5500? If so, then do you have any suggestions?

## Replies

### Reply 1 by Aimee0, 2025-11-07

Hello,

The W5500, due to its hardware TCP/IP stack design, requires communication to pass through the physical network layer.
Therefore, it is not possible for a client socket to connect directly to a server socket on the same chip.

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Source: https://maker.wiznet.io/forum/15927