Troubleshooting

See all UNIX related articles/faq
I‘m trying to login using ssh keys but server is only allows to login me using a password. The following message is logged into my Linux or Unix server /var/log/secure or /var/log/auth.log file:

Feb 25 06:36:50 ns5 sshd[26681]: Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys2

Here is another message:

May 24 18:28:35 ls-www-1 sshd[531320]: Connection closed by 18.1.2.3 port 43640 [preauth]
May 24 18:28:44 ls-www-1 sshd[531322]: Authentication refused: bad ownership or modes for file /home/admin/.ssh/authorized_keys
May 24 18:28:44 ls-www-1 sshd[531322]: Connection closed by authenticating user admin 18.1.2.3 port 43650 [preauth]

How do I fix this problem?
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See all UNIX related articles/faq
How do I capture a specific protocol or port, such as 80 (HTTP) or 443 (HTTPS), using the TCPDump tool under Linux/UNIX? How do I record traffic with TCPDump and find problems later on with my network or server issues? Let’s dive into the nitty-gritty of capturing and analyzing your network traffic for trapshooting network and server issues.
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See all LXD related Howtos/Tutorials
I am a big fan of LXD, a next-generation Linux system container manager and default on Ubuntu. It allows me to run desktop apps or server apps in an isolated environment. Ubuntu provides LXD with robust security in mind. However, this might lead to undesired side effects, such as individual packages under OpenSUSE or CentOS Linux may not be updated. One such package is the filesystem package. Let us see how to fix Error: Transaction failed when you try to update filesystem package under CentOS, OpenSUSE, and other Linux containers running under LXD.
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Nginx upstream sent too big header while reading response header from upstream

See all Nginx webserver related FAQ
I am getting the following error and my app stops working:
    2020/07/12 14:32:03 [error] 45625#45625: *10918 upstream sent too big header while reading response header from upstream, client: 139.xxx.yyy.zzz, server: www.nixcraft.com, request: “POST /app/mg/posts HTTP/2.0”, upstream: “fastcgi://unix:/run/php/php-fpm.sock:”, host: “www.nixcraft.com”, referrer: “https://www.nixcraft.com/mg/admin/index.app”
How do I fix this error for Nginx web server running on Linux or Unix-like systems?
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