---
title: "[Solved] W5500 ignores \"Wi-Fi\" ARP request with padding"
url: "https://maker.wiznet.io/forum/12108"
markdown_url: "https://maker.wiznet.io/forum/12108/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Fierefly"
created: "2017-01-23T17:18:20+09:00"
last_activity: "2017-05-04T08:39:40+09:00"
language: "en"
views: 1427
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# [Solved] W5500 ignores "Wi-Fi" ARP request with padding

## Question

Asked by Fierefly on 2017-01-23 in Ethernet Chips.

Hi,

I’ve noticed that if I use the scheme PC-Ethernet-Router-Ethernet-W5500 (I) all comunication is OK, but on using PC-WiFi-Router-Ethernet-W5500 (II) all fails, even ping. Wireshark analyse showed, that in scheme II ARP packet has 18 padding bytes, and w5500 ignored these packets. I tried 2 development boards with w5500, with the same result. Please, advice what to do for getting reply for type II packets. Wireshark log and screenshots included.
Thanks.

[![](https://maker.wiznet.io/forum_uploads/wiznet/original/1X/59547e83585af0ed0fffef8a4399962827712af8.jpg) 1920×830 768 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/1X/59547e83585af0ed0fffef8a4399962827712af8.jpg)

[![](https://maker.wiznet.io/forum_uploads/wiznet/original/1X/7765026eda3b343a02b38896794f49f05e539dcb.jpg) 1890×825 720 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/1X/7765026eda3b343a02b38896794f49f05e539dcb.jpg)

[packets capture.zip](https://maker.wiznet.io/forum/legacyFile.asp?path=zZ319R1X2vnfbBSQf6kkDOPwQyt.zip) (707 Bytes)

## Replies

### Reply 1 by Eugeny, 2017-01-23

Change MAC address of the device from 03:08:DC:00:AB:CD to, for example, 00:08:DC:00:AB:CD, and try again.

### Reply 2 by Fierefly, 2017-01-24

It works! Thanks ![:slight_smile:](https://emoji.discourse-cdn.com/twitter/slight_smile.png?v=12)

### Reply 3 by Eugeny, 2017-01-24

Conclusion - bits 0 and 1 of the MSB of MAC address should be used with caution as they are reserved for special purposes: [en.wikipedia.org/wiki/MAC_addre … _vs._local](https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local)

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Source: https://maker.wiznet.io/forum/12108