---
title: "W5500 소켓 5,6,7 사용 문제"
url: "https://maker.wiznet.io/forum/14929"
markdown_url: "https://maker.wiznet.io/forum/14929/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "kosal1221"
created: "2023-06-02T06:04:15+09:00"
last_activity: "2023-06-02T11:51:59+09:00"
language: "ko"
views: 146
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 소켓 5,6,7 사용 문제

## Question

Asked by kosal1221 on 2023-06-02 in Ethernet Chips.

안녕하세요 w5500으로 서버에 클라이언트로 접속하고 있습니다.

해당 제품은 소켓 8개를 모두 사용 예정인데

0번은 UDP 로 서버 접속
1~7번은 tcp로 서버 접속을 [클라이언트로동작] 하게 됩니다.

위방식으로 0~ 4번까지는 문제없이 동작하는데

소켓 5~7번은 데이터 통신이 되지 않습니다.

와이어샤크로 찍어보면

RST플레그가 오면서 H/W동작은 close상태로 진입이 되고 있습니다.

해당내용 캡처해서 올려드립니다. 답변 가능하시면 부탁 드리겠습니다.

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/6/6aee80e3679231270ec7ebd34716499426481792.png) image1259×331 15.8 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/6/6aee80e3679231270ec7ebd34716499426481792.png)

## Replies

### Reply 1 by Eugeny, 2023-06-02

RST is a packet sent by the remote network node to identify that it does not want to communicate (anymore) on the port identified in the packet. You send packet, remote node has port closed/released or any other almost-dead state, or the session has been finalized, and that remote node just tells you about its unwillingness. If you see such packets you either do something wrong from TCP flow point of view, but, after consideration, you may decide to accept these RST packets if their presence does not do harm to the overall communication. I can’t tell you more right now because it needs W5500 workflow consideration and consideration of what remote host does and its algorithms.
Note: I believe some “super-intelligent” intermediate devices like bridges and routers may send packets on behalf of remote nodes, therefore not only remote node may need consideration, but also all the devices on the path to remote node.

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Source: https://maker.wiznet.io/forum/14929