---
title: "W5100 TTL value"
url: "https://maker.wiznet.io/forum/13323"
markdown_url: "https://maker.wiznet.io/forum/13323/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Eugeny"
created: "2019-05-16T08:50:15+09:00"
last_activity: "2019-05-30T00:00:26+09:00"
language: "en"
views: 445
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5100 TTL value

## Question

Asked by Eugeny on 2019-05-16 in Ethernet Chips.

Do I understand it properly that I am not able to get information about TTL from IP header in any IP modes (IPRAW/UDP/TCP)?

## Replies

### Reply 1 by irina, 2019-05-23

Hi~ Eugeny

You can confirm the TTL information using Sn_TTL register.

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/a/a15706b7f7e33d1efba925fabeda22df6cfb31cd.png) image1136×132 9.99 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/a/a15706b7f7e33d1efba925fabeda22df6cfb31cd.png)

thanks,
BR
irina

### Reply 2 by Eugeny, 2019-05-23

So Sn_TTL register has TTL information from the last received IP packet? I talk about accessing TTL info for the packets being received, not sent. For example, to achieve task of tracing the route or assessing the distance to specific netowkring device.

### Reply 3 by irina, 2019-05-30

Eugeny:

> So Sn_TTL register has TTL information from the last received IP packet? I talk about accessing TTL info for the packets being received, not sent.

Hi~ Eugeny

I apologize for the late response.
In conclusion,Sn_TTL register is for sending packet. And the TTL of received packet don’t store .
If you need the TTL of received packet, I think you should be use MACRAW mode.
thanks,
BR
irina

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Source: https://maker.wiznet.io/forum/13323