Hi i have latest libssh2, curl, openssh and oroftpd installed from source
curl -V curl 8.18.0 (x86_64-pc-linux-gnu) libcurl/8.18.0 mbedTLS/3.6.5 zlib/1.2.12 libssh2/1.11.1 librtmp/2.3 Release-Date: 2026-01-07 Protocols: dict file ftp ftps http https imap imaps ipfs ipns mqtt pop3 pop3s rtmp rtsp scp sftp smb smbs smtp smtps tftp ws wss Features: alt-svc AsynchDNS HSTS HTTPS-proxy Largefile libz NTLM SSL threadsafe UnixSockets the sftp program from openssh works fine connecting to both proftpd (set up for sftp) and sshd /usr/local/bin/sftp -v -oPort=212 [email protected] curl to the proftpd also set uo for ftps works fine (proftpd ftps : 21 and sfto : 212) /usr/local/bin/curl -v -k -u uwer:pass --ssl-reqd ftp://myserver.net/ i really want to use curl with sftp to connect to either sshd or proftpd instead of using the sftp command i get the same error using curl to either sshd or proftpd with this line /usr/local/bin/curl -v -k -u user sftp://myserver.net:212 * libssh2 cryptography backend: openssl compatible * User: 'user' * Failure establishing ssh session: -8, Unable to exchange encryption keys * closing connection #0 curl: (2) Failure establishing ssh session: -8, Unable to exchange encryption keys this is from th proftpd sftp.log file 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: client (xxx.xxx.xx.xxx:52884) connected to server (xxx.xxx.xx.xxx:212) 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: sent server version 'SSH-2.0-mod_sftp' 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: received client version 'SSH-2.0-libssh2_1.11.1' 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: handling connection from SSH2 client 'libssh2_1.11.1' 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session key exchange: ecdh-sha2-nistp256 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session host key algorithm: rsa-sha2-512 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session server hostkey: rsa-sha2-512 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session client-to-server encryption: [email protected] 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session server-to-client encryption: [email protected] 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session client-to-server compression: none 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: + Session server-to-client compression: none 2026-03-10 16:54:44,027 mod_sftp/1.2.0[7982]: client at xxx.xxx.xx.xxx sent SSH_DISCONNECT message: Shutdown (Application disconnected) i had a curl encryption problem a long time ago and had to add some new cipher line to a ssh/sshd config file but openssh isn't involved here just proftpd amy place to start would be appreciated -- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-users Etiquette: https://curl.se/mail/etiquette.html
