我从一台特定计算机（Mac OS 11.2）到一台特定主机（Ubuntu 18.04.5）出现间歇性 scp 故障。该计算机与其他主机的 scp 没有问题，其他计算机与该主机的 scp 没有问题。我对 ssh 或 mosh 也没有任何问题。
在客户端，我看到：
$ /usr/bin/scp vegan-choux-deflated-big.jpg ps:jtk/
stty: 'standard input': Inappropriate ioctl for device
vegan-choux-deflated-big.jpg 0% 0 0.0KB/s --:-- ETAclient_loop: send disconnect: Broken pipe
lost connection
在我看到的服务器上：
$ sudo journalctl -f
Feb 20 19:12:08 jefftk.com sshd[15856]: Accepted publickey for jefftk from 146.115.48.13 port 65263 ssh2: RSA SHA256:FT44f1oAdXEJtBZTFf1zxC2r6ZxptSES3ZkG/fPmYuk
Feb 20 19:12:08 jefftk.com sshd[15856]: pam_unix(sshd:session): session opened for user jefftk by (uid=0)
Feb 20 19:12:08 jefftk.com systemd-logind[3157]: New session 32 of user jefftk.
Feb 20 19:12:08 jefftk.com systemd[1]: Started Session 32 of user jefftk.
Feb 20 19:12:10 jefftk.com sshd[16050]: ssh_dispatch_run_fatal: Connection from user jefftk 146.115.48.13 port 65263: message authentication code incorrect
Feb 20 19:12:10 jefftk.com sshd[15856]: pam_unix(sshd:session): session closed for user jefftk
Feb 20 19:12:10 jefftk.com systemd-logind[3157]: Removed session 32.
好像message authentication code incorrect是这个问题？
手动指定 MAC ( -o MACs=hmac-sha2-512) 似乎没有效果。
此错误是间歇性的：通常一切正常。
详细上传输出：
$ /usr/bin/scp -v vegan-choux-deflated-big.jpg ps:jtk/
Executing: program /usr/bin/ssh host ps, user (unspecified), command scp -v -t jtk/
OpenSSH_8.1p1, LibreSSL 2.7.3
debug1: Reading configuration data /Users/jefftk/.ssh/config
debug1: /Users/jefftk/.ssh/config line 25: Applying options for ps
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 74: Applying options for *
debug1: hostname canonicalisation enabled, will re-parse configuration
debug1: re-parsing configuration
debug1: Reading configuration data /Users/jefftk/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 60: Applying options for *.com
debug1: /etc/ssh/ssh_config line 64: Applying options for *.*
debug1: /etc/ssh/ssh_config line 74: Applying options for *
debug1: Connecting to www.jefftk.com [163.172.164.150] port 22.
debug1: Connection established.
debug1: identity file /Users/jefftk/.ssh/id_rsa type 0
debug1: identity file /Users/jefftk/.ssh/id_rsa-cert type -1
debug1: identity file /Users/jefftk/.ssh/localhost/id_rsa type -1
debug1: identity file /Users/jefftk/.ssh/localhost/id_rsa-cert type -1
debug1: identity file /Users/jefftk/.ssh/clusterhost/id_rsa type -1
debug1: identity file /Users/jefftk/.ssh/clusterhost/id_rsa-cert type -1
debug1: identity file /Users/jefftk/.ssh/id_ed25519 type -1
debug1: identity file /Users/jefftk/.ssh/id_ed25519-cert type -1
debug1: identity file /Users/jefftk/.ssh/id_ecdsa type -1
debug1: identity file /Users/jefftk/.ssh/id_ecdsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug1: Authenticating to www.jefftk.com:22 as 'jefftk'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:bXmp8R4JOzinavMiXjgpzJk7mjhNiPOQ61NChWaXrDo
debug1: Host 'www.jefftk.com' is known and matches the ECDSA host key.
debug1: Found key in /Users/jefftk/.ssh/known_hosts:115
debug1: rekey out after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 4294967296 blocks
debug1: Will attempt key: publickey ECDSA SHA256:7PPjwtPBwuO+UnzB/Myo/La/ptAQ5EI8YeDoHkpO7wM agent
debug1: Will attempt key: corp/normal ECDSA-CERT SHA256:X7GzO8/fLB5iiNYLqDU/lRz2I7CajWm8WJcKnwv0WnA agent
debug1: Will attempt key: /Users/jefftk/.ssh/id_rsa RSA SHA256:FT44f1oAdXEJtBZTFf1zxC2r6ZxptSES3ZkG/fPmYuk
debug1: Will attempt key: /Users/jefftk/.ssh/localhost/id_rsa
debug1: Will attempt key: /Users/jefftk/.ssh/clusterhost/id_rsa
debug1: Will attempt key: /Users/jefftk/.ssh/id_ed25519
debug1: Will attempt key: /Users/jefftk/.ssh/id_ecdsa
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: publickey ECDSA SHA256:7PPjwtPBwuO+UnzB/Myo/La/ptAQ5EI8YeDoHkpO7wM agent
debug1: Authentications that can continue: publickey,password
debug1: Offering public key: corp/normal ECDSA-CERT SHA256:X7GzO8/fLB5iiNYLqDU/lRz2I7CajWm8WJcKnwv0WnA agent
debug1: Authentications that can continue: publickey,password
debug1: Offering public key: /Users/jefftk/.ssh/id_rsa RSA SHA256:FT44f1oAdXEJtBZTFf1zxC2r6ZxptSES3ZkG/fPmYuk
debug1: Server accepts key: /Users/jefftk/.ssh/id_rsa RSA SHA256:FT44f1oAdXEJtBZTFf1zxC2r6ZxptSES3ZkG/fPmYuk
debug1: Authentication succeeded (publickey).
Authenticated to www.jefftk.com ([163.172.164.150]:22).
debug1: channel 0: new [client-session]
debug1: Requesting [email protected]
debug1: Entering interactive session.
debug1: pledge: network
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug1: Sending command: scp -v -t jtk/
stty: 'standard input': Inappropriate ioctl for device
Sending file modes: C0644 2413695 vegan-choux-deflated-big.jpg
Sink: C0644 2413695 vegan-choux-deflated-big.jpg
vegan-choux-deflated-big.jpg 99% 2336KB 4.8MB/s 00:00 ETAclient_loop: send disconnect: Broken pipe
lost connection