sftp hangs when trying to connect to SFTP server

[Mark Hansen <cygwin@mehconsulting.com>]

Team,

I'm not sure when this started, but I know for sure I was able to do this in the past.

I'm running cygwin on Windows 10 and want to connect to an SFTP server using the 'sftp' command.

Note that when I try to connect to the same SFTP server using a different client, File Zilla, it works.

When I run sftp, it appears to hang. I've run it with -vvvv to get some debugging output and get the following:

1001 jdk16->> sftp -vvvv -P 2100 192.168.160.62
OpenSSH_8.8p1, OpenSSL 1.1.1l  24 Aug 2021
debug1: Reading configuration data /cygdrive/c/Users/mark.hansen/.ssh/config
debug1: /cygdrive/c/Users/mark.hansen/.ssh/config line 1: Applying options for *
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 46: Applying options for *
debug2: resolve_canonicalize: hostname 192.168.160.62 is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/cygdrive/c/Users/mark.hansen/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/cygdrive/c/Users/mark.hansen/.ssh/known_hosts2'
debug3: ssh_connect_direct: entering
debug1: Connecting to 192.168.160.62 [192.168.160.62] port 2100.
debug3: set_sock_tos: set socket 4 IP_TOS 0x48
debug1: Connection established.
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_rsa type 0
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_rsa-cert type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_dsa type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_dsa-cert type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ecdsa type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ecdsa-cert type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ecdsa_sk type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ed25519 type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ed25519-cert type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ed25519_sk type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_xmss type -1
debug1: identity file /cygdrive/c/Users/mark.hansen/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.8
debug1: kex_exchange_identification: banner line 0: 220 Welcome to AT FTP service
debug1: kex_exchange_identification: banner line 1: 530 Please login with USER and PASS.

... after some time ...
debug1: kex_exchange_identification: banner line 2: 421 Timeout.
kex_exchange_identification: Connection closed by remote host
Connection closed by 192.168.160.62 port 2100
Connection closed

Here is my local config file (.ssh/config):

Host *
     Protocol 2
     ForwardX11Trusted yes
     ForwardX11 yes

Here is /etc/ssh_config:

Host *
ForwardX11 yes



Yesterday, I upgraded to the latest cygwin packages and now the cygwin DLL is version 3.3.2

I tried running the command with the login user name on the command line (user@192.168.160.62) and
assuming it was just waiting for the password, I tried entering it, but the characters were
just echoed to the terminal and the process continued to hang.

Any idea what is causing this? What can I do to troubleshoot this further?