Hello, I manage around 50 FreeBSD servers and I have created a script which does some work every 5 minutes. Actually this script transfers some files to/from the central server, which is running a OpenSSH's sshd (OpenSSH_4.5p1 FreeBSD-20061110, OpenSSL 0.9.7e-p1 25 Oct 2004). So I use sftp (I have also tried scp) on client sides to perform the task.
The problem is, that (apparently because all the servers start transferring files at approximately the same time), some clients are able to do the transfers and others are not. If the connection is unsuccessful, I get this on client side (sftp -v): Connecting to a.b.c.d... OpenSSH_4.2p1 FreeBSD-20050903, OpenSSL 0.9.7e-p1 25 Oct 2004 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Connecting to a.b.c.d [a.b.c.d] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/id_rsa type 1 debug1: identity file /root/.ssh/id_dsa type -1 ssh_exchange_identification: Connection closed by remote host Connection closed So it looks like sshd on the central server just drops the connection. I have also tried to turn on DEBUG mode for sshd on central server, but there is way too much of the output to analyze. I've grepped (-i) the log file for the word "error" but no lines matched. If the connection is successful, however, I get this on client side: Connecting to a.b.c.d... OpenSSH_4.2p1 FreeBSD-20050903, OpenSSL 0.9.7e-p1 25 Oct 2004 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Connecting to a.b.c.d [a.b.c.d] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/id_rsa type 1 debug1: identity file /root/.ssh/id_dsa type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_4.5p1 FreeBSD-20061110 debug1: match: OpenSSH_4.5p1 FreeBSD-20061110 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_4.2p1 FreeBSD-20050903 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-cbc hmac-md5 none debug1: kex: client->server aes128-cbc hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host 'a.b.c.d' is known and matches the DSA host key. debug1: Found key in /root/.ssh/known_hosts:30 debug1: ssh_dss_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey,keyboard-interactive debug1: Next authentication method: publickey debug1: Offering public key: /root/.ssh/id_rsa debug1: Server accepts key: pkalg ssh-rsa blen 277 debug1: read PEM private key done: type RSA debug1: Authentication succeeded (publickey). debug1: channel 0: new [client-session] debug1: Entering interactive session. debug1: Sending subsystem: sftp sftp> get file1 file2 Fetching file1 to file2 debug1: client_input_channel_req: channel 0 rtype exit-status reply 0 debug1: channel 0: free: client-session, nchannels 1 debug1: fd 0 clearing O_NONBLOCK debug1: fd 2 clearing O_NONBLOCK debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 0.4 seconds debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0 debug1: Exit status 0 Do you have any ideas why the central server's sshd drops the connections? It's a modern machine with a good network card on a fast link, so this should not be a problem. Also, before I used plain FTP and HTTP transfers and everything worked OK. Thanks, Nejc
