With Telnet65 from Oliver Schmidt you can telnet from a Apple IIe enhanced with the Uthernet and the Uthernet II.
I made a fine working connection to A 80's Apple II BBS - a80sappleiibbs.ddns.net:6502
So you don't have to connect to another card like WiFi232 or Raspberry PI with tcpser (although they work very good).
I had to change the slot from 3 (where Telnet65 expects the Uthernet) to slot 5 (where mine is). I used for that Disk Fixer V4.0 (the world’s most powerful 5.25” sector editor on Earth).
You have to change the fourth byte of Telnet65:
1. Press "O"
2. Press Return
3. Right arrow to Dos3.3
4. Press P for ProDos
5. Press Escape 2 times
6. Press "D"
7. Choose Telnet65
8. Press "Y"
9. Press "K" 3 times to reach fourth byte (03)
10. Press Return
11. Write 0X while X is the Slot where your Uthernet is
12. Press Escape
13. Press "W"
14. Press 2times Return to write to disk