关于升级openssh后ulimit不生效问题的解决方法

if you just want sshd to honor the settings you made in /etc/security/limits.conf, you should make sure you have UsePAM yes in /etc/ssh/sshd_config, and /etc/pam.d/sshd lists session    required      pam_limits.so (or otherwise includes another file that does so).

#  ./configure --prefix=/usr  --sysconfdir=/etc/ssh--with-md5-passwords  --with-zlib  --with-pam

#  make  -j  4 &&  make  install

# cat  /etc/pam.d/sshd

############################

#%PAM-1.0

auth      required    pam_sepermit.so

auth      substack    password-auth

auth      include      postlogin

# Used with polkit to reauthorize users in remote sessions

-auth      optional    pam_reauthorize.so prepare

account    required    pam_nologin.so

account    include      password-auth

password  include      password-auth

# pam_selinux.so close should be the first session rule

session    required    pam_selinux.so close

session    required    pam_loginuid.so

# pam_selinux.so open should only be followed by sessions to be executed in the user context

session    required    pam_selinux.so open env_params

session    required    pam_namespace.so

session    optional    pam_keyinit.so force revoke

session    include      password-auth

session    include      postlogin

# Used with polkit to reauthorize users in remote sessions

-session  optional    pam_reauthorize.so prepare

############################

卸载系统自带的openssh之前，最好是备份一下/etc/pam.d/sshd，编译完之后 ，查看/etc/pam.d如果没有sshd文件，就恢复备份。

参考

Linux升级openssh后打开打开文件数ulimit重置为1024问题解决

https://codeantenna.com/a/o1Da284aDT

https://blog.csdn.net/zilong_zilong/article/details/94021543

ulimit -n修改之后不生效

https://www.codenong.com/cs106689533/

OpenSSH由7.4编译升级到8.0之后出现一些问题

https://www.cnblogs.com/augusite/p/11155654.html

Linux实例由于Ulimit限制原因导致SSH登录后系统异常

https://help.aliyun.com/document_detail/41483.html

limits.conf - configuration file for the pam_limits module

http://manpages.ubuntu.com/manpages/jammy/en/man5/limits.conf.5.html

ulimit -n not changing - values limits.conf has no effect

https://serverfault.com/questions/569288/ulimit-n-not-changing-values-limits-conf-has-no-effect

OpenSSH一键升级脚本

https://www.cnblogs.com/RXDXB/p/12145644.html

https://blog.51cto.com/kk876435928/2419589

任意版本openssh批量升级脚本

https://www.izhuhn.cn/index.php/2019/05/29/%E4%BB%BB%E6%84%8F%E7%89%88%E6%9C%ACopenssh%E6%89%B9%E9%87%8F%E5%8D%87%E7%BA%A7%E8%84%9A%E6%9C%AC/