Re: [Proftpd-user] Response error from backend control channel with mod_proxy and mod_sftp

> I restart proftpd with this trace conf and now I have this in the log :
>
> 2023-07-19 15:23:30,539 [10] <ssh2:9>: loading host key from file 
> '/opt/proftpd/conf/keys/test-key-rsa'
> 2023-07-19 15:23:30,542 [10] <ssh2:4>: using 
> '/opt/proftpd/conf/keys/test-key-rsa' as RSA hostkey (2048 bits)
> 2023-07-19 15:23:30,544 [10] <proxy.conn:12>: connecting to backend 
> address 10.1.80.171#8022 from 10.1.80.139#36381
> 2023-07-19 15:23:30,547 [10] <proxy.conn:5>: successfully connected to 
> 10.1.80.171#8022 from 10.1.80.139#36381
> 2023-07-19 15:23:30,547 [10] <proxy.reverse:8>: connected to backend 
> 'sftp://10.1.80.171:8022' in 3 ms
> 2023-07-19 15:23:30,547 [10] <proxy:9>: removed PRE_CMD APPE mod_xfer 
> handlers
> 2023-07-19 15:23:30,547 [10] <proxy:9>: removed PRE_CMD RETR mod_xfer 
> handlers
> 2023-07-19 15:23:30,547 [10] <proxy:9>: removed PRE_CMD STOR mod_xfer 
> handlers
> 2023-07-19 15:23:30,547 [10] <proxy:9>: removed PRE_CMD STOU mod_xfer 
> handlers
> 2023-07-19 15:23:30,548 [10] <proxy:15>: found group 'NONE' for command 
> 'SSH-2.0-OPENSSH_8.9P1'
> 2023-07-19 15:23:30,548 [10] <proxy:9>: chrooted session to 
> '/ftp-proxytables/empty'
> 2023-07-19 15:23:30,548 [10] <proxy:7>: error checking for async 
> messages from the backend server: Invalid argument
>
> Using the command line sftp client, it starts but the connection hangs 
> and the prompt never returns :
>
> $ sftp -vvv [email protected]
> OpenSSH_8.9p1 Ubuntu-3ubuntu0.1, OpenSSL 3.0.2 15 Mar 2022
> debug1: Reading configuration data /home/sba/.ssh/config
> debug1: Reading configuration data /etc/ssh/ssh_config
> debug1: /etc/ssh/ssh_config line 19: include 
> /etc/ssh/ssh_config.d/*.conf matched no files
> debug1: /etc/ssh/ssh_config line 21: Applying options for *
> debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> 
> '/home/sba/.ssh/known_hosts'
> debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> 
> '/home/sba/.ssh/known_hosts2'
> debug2: resolving "my.server" port 22
> debug3: resolve_host: lookup my.server:22
> debug3: ssh_connect_direct: entering
> debug1: Connecting to my.server [xxx.xxx.xxx.xxx] port 22.
> debug3: set_sock_tos: set socket 3 IP_TOS 0x10
> debug1: Connection established.
> debug1: identity file /home/sba/.ssh/id_rsa type 0
> debug1: identity file /home/sba/.ssh/id_rsa-cert type -1
> debug1: identity file /home/sba/.ssh/id_ecdsa type -1
> debug1: identity file /home/sba/.ssh/id_ecdsa-cert type -1
> debug1: identity file /home/sba/.ssh/id_ecdsa_sk type -1
> debug1: identity file /home/sba/.ssh/id_ecdsa_sk-cert type -1
> debug1: identity file /home/sba/.ssh/id_ed25519 type -1
> debug1: identity file /home/sba/.ssh/id_ed25519-cert type -1
> debug1: identity file /home/sba/.ssh/id_ed25519_sk type -1
> debug1: identity file /home/sba/.ssh/id_ed25519_sk-cert type -1
> debug1: identity file /home/sba/.ssh/id_xmss type -1
> debug1: identity file /home/sba/.ssh/id_xmss-cert type -1
> debug1: identity file /home/sba/.ssh/id_dsa type -1
> debug1: identity file /home/sba/.ssh/id_dsa-cert type -1
> debug1: Local version string SSH-2.0-OpenSSH_8.9p1 Ubuntu-3ubuntu0.1
> debug1: kex_exchange_identification: banner line 0: 530 Please login 
> with USER and PASS

Interesting.  What's the output you see when you use `sftp -vvv` directly against that MFT service, i.e. `sftp -vvv -P 8022 [email protected]`?

Cheers,
TJ


_______________________________________________
ProFTPD Users List   <[email protected]>
Unsubscribe problems?
http://www.proftpd.org/list-unsub.html