Overview
This article provides solutions to common PuTTY problems — non-English filenames showing as ??????, idle SSH connections dropping, and the "No supported authentication methods" connection error.
How do I fix common PuTTY issues?
The following sections show you how to fix translation and connection issues in PuTTY.
Why do non-English filenames appear as ??????
Directory and filenames that contain non-English/Asian characters may sometimes appear as ?????? or even as a corrupt file in PuTTY.
If you experience this issue with your filenames or content not showing up correctly, you should add the following to your .bash_profile file to enable UTF support. See the following articles for instructions on how to update the file (depending on if you're using an FTP client or SSH):
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
export LANGUAGE=en_US.UTF-8
export G_FILENAME_ENCODING=UTF-8
UTF-8 is most likely enabled already. You can check in your terminal by entering the locale command:
[server]$ locale LANG=en_US.UTF-8 LANGUAGE=
LC_CTYPE="en_US.UTF-8" LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8" LC_COLLATE=C LC_MONETARY="en_US.UTF-8" LC_MESSAGES="en_US.UTF-8" LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8" LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8" LC_MEASUREMENT="en_US.UTF-8" LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=
You can see the first line is LANG=en_US.UTF-8. If the listings are still not appearing correctly, it’s most likely because of the terminal client you’re using. In PuTTY, you can manually adjust the translation option to UTF-8:
- Open the PuTTY general configuration.
- In the left Category list section, select Window > Translation.
- In the dropdown for Remote character set, choose UTF-8.
- Go back to the Session category and make sure to save your current session with all settings.
When you log in again using PuTTY, the non-English characters display correctly.
Why are my idle connections dropping?
DreamHost and other ISPs may kill SSH connections that remain idle longer than a certain number of minutes. In PuTTY (for Windows), you are able to adjust that setting in the PuTTY Configuration box as follows:
- Open the PuTTY general configuration.
- In the left Category list section, select Connection.
- In the Seconds between keepalives (0 to turn off) field, enter 15.
- Check the Enable TCP keepalives (SO_KEEPALIVE option) box.
The SSH client asks the server for a sign of life every 15 seconds, thus keeping the connection open.
Why do I get a connection error?
You may see the following error when connecting:
No supported authentication methods available (server sent public key)
This could be an issue with how the public key was saved. PuttyGen will create a public key file that looks like this:
---- BEGIN SSH2 PUBLIC KEY ---- Comment: "ed25519-key-20250305" AAAAC3NzaC1lZDI1NTE5AAAAICSt22nRRmm8g+d0E6Cpor9kTJbgw1dFsufSyj1K I1rf ---- END SSH2 PUBLIC KEY ----
The key needs to be saved on a single line. Open the key in PuttyGen, copy it from there, and then paste it into a program such as Notepad. This results in the key being saved on 1 line:
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICSt22nRRmm8g+d0E6Cpor9kTJbgw1dFsufSyj1KI1rf ed25519-key-20250305
Paste this from Notepad into the authorized_keys file on your server, and it should work. See this page for a more detailed explanation.