SSH远程登录RaspberryPi命令行响应缓慢问题

Posted 2023-02-14 lida2003

SSH远程登录RaspberryPi命令行响应缓慢问题

• 1. 问题
• 2. 分析
• 3. 解决
• • 3.1 去掉PAM部分鉴权模块
  • 3.2 去掉sshd的DNS设置
  • 3.3 无线WiFi信号优化
  • • 方法一：ifconfig操作
    • 方法二：内核自动检测
• 4. 结果
• 5. 补充资料
• • 5.1 [排除wifi网卡功率自管理问题](https://raspberrypi.stackexchange.com/questions/96606/make-iw-wlan0-set-power-save-off-permanent)
  • 5.2 hostname已经修改（不存在重复）

1. 问题

远程登录Raspberry Zero WH命令行，操作响应缓慢，应该说极其缓慢，简直无法仍受。

注：刚开始烧录映像文件的时候，倒是没有类似的问题。

2. 分析

通过SSH日志文件分析响应缓慢问题，修改配置参数“LogLevel”将其设置为最大级别DEBUG3，这样我们就可以通过SSH服务日志文件“/var/log/auth.log”日志的详细信息了解缓慢问题出在哪里。

$ sudo nano /etc/ssh/sshd_config

3. 解决

3.1 去掉PAM部分鉴权模块

$ sudo nano /etc/pam.d/common-session

3.2 去掉sshd的DNS设置

$ sudo nano /etc/ssh/sshd_config

3.3 无线WiFi信号优化

鉴于Raspberry Zero WH板子上天线也是非常紧凑的，且2.4G也可能存在遮挡导致信号相对较差，如果能将报文长度减小，受干扰的机会就会减少。


这里确实找到网络上的一个方法，减少MTU的大小。

方法一：ifconfig操作

$ sudo ifconfig wlan0

$ sudo ifconfig wlan0 mtu 500
$ sudo ifconfig wlan0

方法二：内核自动检测

比较优雅的操作方法是在/etc/sysctl.d/99-sysctl.conf加上net.ipv4.tcp_mtu_probing = 1：

$ sudo vi /etc/sysctl.d/99-sysctl.conf
$ sudo sysctl --system

4. 结果

实际结果：感觉确实不会超级相应缓慢，但是还是有点磕磕碰碰的感觉。

1. 树莓派直接放在路由器边上（可是距离）
2. 内核自动调参，实际MTU1500没有什么变化（排除无线通信干扰）
3. 整体感觉确实比之前无法忍受的情况有所改善，但是还是有点磕磕碰碰。

应该还有问题，但是不知道具体是什么，存疑！

• 14:16:20 - 14:17:06 完成登录，耗时46秒（含用户密码输入）
• 14:16:28 - 3 14:16:47 环境变量复制，耗时19秒（太长了）
• 14:16:47 - 14:17:01 一段空隙时间，长度14秒（不太清楚具体工作）
• 14:17:01 - 14:17:06 pam_unix鉴权耗时5秒
• 其他不概述耗时：46 - 19 -14 - 5 = 8秒

注：有知道的兄弟朋友，请批注指点下，谢谢！

$ cat /var/log/auth.log
Feb  3 14:16:20 PiCam sshd[410]: debug3: fd 5 is not O_NONBLOCK
Feb  3 14:16:20 PiCam sshd[410]: debug1: Forked child 783.
Feb  3 14:16:20 PiCam sshd[410]: debug3: send_rexec_state: entering fd = 8 config len 306
Feb  3 14:16:20 PiCam sshd[410]: debug3: ssh_msg_send: type 0
Feb  3 14:16:20 PiCam sshd[410]: debug3: send_rexec_state: done
Feb  3 14:16:20 PiCam sshd[783]: debug3: oom_adjust_restore
Feb  3 14:16:20 PiCam sshd[783]: debug1: Set /proc/self/oom_score_adj to 0
Feb  3 14:16:20 PiCam sshd[783]: debug1: rexec start in 5 out 5 newsock 5 pipe 7 sock 8
Feb  3 14:16:21 PiCam sshd[783]: debug1: inetd sockets after dupping: 3, 3
Feb  3 14:16:21 PiCam sshd[783]: Connection from 192.168.68.52 port 65369 on 192.168.68.245 port 22
Feb  3 14:16:21 PiCam sshd[783]: debug1: Client protocol version 2.0; client software version PuTTY_Release_0.78
Feb  3 14:16:21 PiCam sshd[783]: debug1: no match: PuTTY_Release_0.78
Feb  3 14:16:21 PiCam sshd[783]: debug1: Local version string SSH-2.0-OpenSSH_7.9p1 Raspbian-10+deb10u2+rpt1
Feb  3 14:16:21 PiCam sshd[783]: debug2: fd 3 setting O_NONBLOCK
Feb  3 14:16:21 PiCam sshd[783]: debug3: ssh_sandbox_init: preparing seccomp filter sandbox
Feb  3 14:16:21 PiCam sshd[783]: debug2: Network child is on pid 784
Feb  3 14:16:21 PiCam sshd[783]: debug3: preauth child monitor started
Feb  3 14:16:21 PiCam sshd[783]: debug3: privsep user:group 107:65534 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: permanently_set_uid: 107/65534 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: ssh_sandbox_child: setting PR_SET_NO_NEW_PRIVS [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: ssh_sandbox_child: attaching seccomp filter program [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: list_hostkey_types: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: send packet: type 20 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: SSH2_MSG_KEXINIT sent [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: receive packet: type 20 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: SSH2_MSG_KEXINIT received [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: local server KEXINIT proposal [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: KEX algorithms: curve25519-sha256,[e-mail],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: host key algorithms: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: ciphers ctos: [e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail],[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: ciphers stoc: [e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail],[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: MACs ctos: [e-mail],[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-sha1 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: MACs stoc: [e-mail],[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-sha1 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: compression ctos: none,[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: compression stoc: none,[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: languages ctos:  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: languages stoc:  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: first_kex_follows 0  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: reserved 0  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: peer client KEXINIT proposal [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: KEX algorithms: [e-mail],curve448-sha512,curve25519-sha256,[e-mail],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group18-sha512,diffie-hellman-group17-sha512,diffie-hellman-group16-sha512,diffie-hellman-group15-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,rsa2048-sha256,rsa1024-sha1,diffie-hellman-group1-sha1,ext-info-c [prea
Feb  3 14:16:21 PiCam sshd[783]: debug2: host key algorithms: ssh-ed25519,ssh-ed448,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: ciphers ctos: aes256-ctr,aes256-cbc,[e-mail],aes192-ctr,aes192-cbc,aes128-ctr,aes128-cbc,[e-mail],[e-mail],[e-mail],3des-ctr,3des-cbc,blowfish-ctr,blowfish-cbc,arcfour256,arcfour128 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: ciphers stoc: aes256-ctr,aes256-cbc,[e-mail],aes192-ctr,aes192-cbc,aes128-ctr,aes128-cbc,[e-mail],[e-mail],[e-mail],3des-ctr,3des-cbc,blowfish-ctr,blowfish-cbc,arcfour256,arcfour128 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: MACs ctos: hmac-sha2-256,hmac-sha1,hmac-sha1-96,hmac-md5,[e-mail],[e-mail],[e-mail],[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: MACs stoc: hmac-sha2-256,hmac-sha1,hmac-sha1-96,hmac-md5,[e-mail],[e-mail],[e-mail],[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: compression ctos: none,zlib,[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: compression stoc: none,zlib,[e-mail] [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: languages ctos:  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: languages stoc:  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: first_kex_follows 0  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: reserved 0  [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: kex: algorithm: curve25519-sha256 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: kex: host key algorithm: ssh-ed25519 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: kex: client->server cipher: aes256-ctr MAC: hmac-sha2-256 compression: none [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: kex: server->client cipher: aes256-ctr MAC: hmac-sha2-256 compression: none [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: receive packet: type 30 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_sshkey_sign entering [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_request_send entering: type 6 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:21 PiCam sshd[783]: debug3: monitor_read: checking request 6
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_answer_sign
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_answer_sign: hostkey proof signature 0x14cec20(83)
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_request_send entering: type 7
Feb  3 14:16:21 PiCam sshd[783]: debug2: monitor_read: 6 used once, disabling now
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_sshkey_sign: waiting for MONITOR_ANS_SIGN [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_request_receive_expect entering: type 7 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: mm_request_receive entering [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: send packet: type 31 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: send packet: type 21 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: set_newkeys: mode 1 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: rekey after 4294967296 blocks [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: SSH2_MSG_NEWKEYS sent [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: expecting SSH2_MSG_NEWKEYS [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: send packet: type 7 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: receive packet: type 21 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: SSH2_MSG_NEWKEYS received [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug2: set_newkeys: mode 0 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: rekey after 4294967296 blocks [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug1: KEX done [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: receive packet: type 5 [preauth]
Feb  3 14:16:21 PiCam sshd[783]: debug3: send packet: type 6 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: receive packet: type 50 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug1: userauth-request for user pi service ssh-connection method none [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug1: attempt 0 failures 0 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_getpwnamallow entering [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_send entering: type 8 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_getpwnamallow: waiting for MONITOR_ANS_PWNAM [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_receive_expect entering: type 9 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_receive entering [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:24 PiCam sshd[783]: debug3: monitor_read: checking request 8
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_answer_pwnamallow
Feb  3 14:16:24 PiCam sshd[783]: debug2: parse_server_config: config reprocess config len 306
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_answer_pwnamallow: sending MONITOR_ANS_PWNAM: 1
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_send entering: type 9
Feb  3 14:16:24 PiCam sshd[783]: debug2: monitor_read: 8 used once, disabling now
Feb  3 14:16:24 PiCam sshd[783]: debug2: input_userauth_request: setting up authctxt for pi [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_start_pam entering [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_send entering: type 100 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_inform_authserv entering [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_send entering: type 4 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug2: input_userauth_request: try method none [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: user_specific_delay: user specific delay 0.000ms [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: ensure_minimum_time_since: elapsed 35.713ms, delaying 32.016ms (requested 8.466ms) [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:24 PiCam sshd[783]: debug3: monitor_read: checking request 100
Feb  3 14:16:24 PiCam sshd[783]: debug1: PAM: initializing for "pi"
Feb  3 14:16:24 PiCam sshd[783]: debug1: PAM: setting PAM_RHOST to "192.168.68.52"
Feb  3 14:16:24 PiCam sshd[783]: debug1: PAM: setting PAM_TTY to "ssh"
Feb  3 14:16:24 PiCam sshd[783]: debug2: monitor_read: 100 used once, disabling now
Feb  3 14:16:24 PiCam sshd[783]: debug3: userauth_finish: failure partial=0 next methods="publickey,password" [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: send packet: type 51 [preauth]
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:24 PiCam sshd[783]: debug3: monitor_read: checking request 4
Feb  3 14:16:24 PiCam sshd[783]: debug3: mm_answer_authserv: service=ssh-connection, style=, role=
Feb  3 14:16:24 PiCam sshd[783]: debug2: monitor_read: 4 used once, disabling now
Feb  3 14:16:26 PiCam sshd[783]: debug3: receive packet: type 2 [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: Received SSH2_MSG_IGNORE [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: receive packet: type 50 [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug1: userauth-request for user pi service ssh-connection method password [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug1: attempt 1 failures 0 [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug2: input_userauth_request: try method password [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: mm_auth_password entering [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: mm_request_send entering: type 12 [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: mm_auth_password: waiting for MONITOR_ANS_AUTHPASSWORD [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: mm_request_receive_expect entering: type 13 [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: mm_request_receive entering [preauth]
Feb  3 14:16:26 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:26 PiCam sshd[783]: debug3: monitor_read: checking request 12
Feb  3 14:16:26 PiCam sshd[783]: debug3: PAM: sshpam_passwd_conv called with 1 messages
Feb  3 14:16:27 PiCam sshd[783]: debug1: PAM: password authentication accepted for pi
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_answer_authpassword: sending result 1
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_send entering: type 13
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_receive_expect entering: type 102
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:27 PiCam sshd[783]: debug1: do_pam_account: called
Feb  3 14:16:27 PiCam sshd[783]: debug2: do_pam_account: auth information in SSH_AUTH_INFO_0
Feb  3 14:16:27 PiCam sshd[783]: debug3: PAM: do_pam_account pam_acct_mgmt = 0 (Success)
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_send entering: type 103
Feb  3 14:16:27 PiCam sshd[783]: Accepted password for pi from 192.168.68.52 port 65369 ssh2
Feb  3 14:16:27 PiCam sshd[783]: debug1: monitor_child_preauth: pi has been authenticated by privileged process
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_get_keystate: Waiting for new keys
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_receive_expect entering: type 26
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_receive entering
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_get_keystate: GOT new keys
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_auth_password: user authenticated [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: user_specific_delay: user specific delay 0.000ms [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: ensure_minimum_time_since: elapsed 348.066ms, delaying 193.765ms (requested 8.466ms) [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_do_pam_account entering [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_send entering: type 102 [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_receive_expect entering: type 103 [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_receive entering [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_do_pam_account returning 1 [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: send packet: type 52 [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_request_send entering: type 26 [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug3: mm_send_keystate: Finished sending state [preauth]
Feb  3 14:16:27 PiCam sshd[783]: debug1: monitor_read_log: child log fd closed
Feb  3 14:16:27 PiCam sshd[783]: debug3: ssh_sandbox_parent_finish: finished
Feb  3 14:16:27 PiCam sshd[783]: debug1: PAM: establishing credentials
Feb  3 14:16:27 PiCam sshd[783]: debug3: PAM: opening session
Feb  3 14:16:27 PiCam sshd[783]: debug2: do_pam_session: auth information in SSH_AUTH_INFO_0
Feb  3 14:16:27 PiCam sshd[783]: pam_unix(sshd:session): session opened for user pi by (uid=
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