Unable to connect to legacy SSH machines #1

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opened 2026-04-14 12:54:36 +02:00 by tux · 1 comment

tux commented

2026-04-14 12:54:36 +02:00

Owner

SSH connection to machines which do not provide modern algorithm fails:

2026-04-14T10:51:09.164984Z ERROR shellstation_lib::ssh: SSH target connection failed host=xxx.xxx.xxx.xxx port=22 error=No common Kex algorithm - ours: ["mlkem768x25519-sha256", "curve25519-sha256", "curve25519-sha256@libssh.org", "diffie-hellman-group-exchange-sha256", "diffie-hellman-group18-sha512", "diffie-hellman-group17-sha512", "diffie-hellman-group16-sha512", "diffie-hellman-group15-sha512", "diffie-hellman-group14-sha256"], theirs: ["diffie-hellman-group-exchange-sha1", "diffie-hellman-group14-sha1"]

The file at C:\Users$USER.ssh\config was created as mitigation:

Host *
  Ciphers +3des-cbc,aes256-ctr,aes128-ctr,aes256-cbc,aes128-cbc
  HostKeyAlgorithms +ssh-rsa,ecdsa-sha2-nistp521
  PubkeyAcceptedKeyTypes +ssh-rsa
  KexAlgorithms +diffie-hellman-group1-sha1,diffie-hellman-group14-sha1
  RequiredRSASize 1024

but the issue remains.

SSH connection to machines which do not provide modern algorithm fails: `2026-04-14T10:51:09.164984Z ERROR shellstation_lib::ssh: SSH target connection failed host=xxx.xxx.xxx.xxx port=22 error=No common Kex algorithm - ours: ["mlkem768x25519-sha256", "curve25519-sha256", "curve25519-sha256@libssh.org", "diffie-hellman-group-exchange-sha256", "diffie-hellman-group18-sha512", "diffie-hellman-group17-sha512", "diffie-hellman-group16-sha512", "diffie-hellman-group15-sha512", "diffie-hellman-group14-sha256"], theirs: ["diffie-hellman-group-exchange-sha1", "diffie-hellman-group14-sha1"]` The file at C:\Users\$USER\.ssh\config was created as mitigation: ``` Host * Ciphers +3des-cbc,aes256-ctr,aes128-ctr,aes256-cbc,aes128-cbc HostKeyAlgorithms +ssh-rsa,ecdsa-sha2-nistp521 PubkeyAcceptedKeyTypes +ssh-rsa KexAlgorithms +diffie-hellman-group1-sha1,diffie-hellman-group14-sha1 RequiredRSASize 1024 ``` but the issue remains.

tux commented

2026-04-14 16:32:00 +02:00

Author

Owner

Fixed in #3d6efa1aff, in release 0.9.4

Fixed in #3d6efa1afff55fb545ab47cf03815d191b12a561, in [release 0.9.4](https://git.fiedler.live/tux/shellstation/src/tag/v0.9.4)