Ethernet shield gives unknown command at startup connection

Projects Programming
1

Hello,

I got an Arduino Mega + Ethernet shield (V2).
On it I run the DHCP Chat Server with of course modifications.

When I connect to the Arduino setup with TeraTerm in Telnet mode, then I receive a unknown command at the arduino side (sending all data from the Ethernet shield by a serial connection to the screen).

This happens also when the setup is in idle mode (waiting for user input by telnet) between 5 to 10 min.

I have no idea where to look for this issue. Is this some establishment data?
Anyone with the same issue or any idea where to look for?

Thanks in advance!

2

Do you plan to share what you get on the arduino side or do we need to guess?

Have you tried with a simpler program on the arduino to log in the console what you get upon establishing your telnet connection?

3

You are connecting to a Telnet server. Have you looked at the Telnet protocol specification to see what that message means?

4

J-M-L:
Do you plan to share what you get on the arduino side or do we need to guess?

Have you tried with a simpler program on the arduino to log in the console what you get upon establishing your telnet connection?

Point taken, I checked with the example project of the ethernet shield (DhcpChatServer) and then I receive
teraterm settings: TCP/IP, Service:Telnet, TCP port#:23, Protocol: IPv4
The data that I receive at the Arduino side after making the connection:

"⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮K" and 2 rows more of this kind of data.

johnwasser:
You are connecting to a Telnet server. Have you looked at the Telnet protocol specification to see what that message means?

I did not, mostly because I have absolutely no clue what this data is?
Could you help me with the Telnet protocol specifications?

5

i have tried it with windows CMD in Telnet setting and there the unknown commands are not there so @johnwasser, I think you are correct. I assume that it is in the Telnet settings by TeraTerm.