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nginx: Send HTTP User Agent Requests To Specific Backend Server

I've tons of images, css and javascript hosted at backend server IP and How do I make sure nginx reverse proxy load balancer always send all http_user_agent requests coming from "Mozilla" to server and MSIE to server only?
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BIND DNS: Disable Dynamic Updates

BIND9 dynamic updates allow remote servers to add, delete, or modify any entries in my zone file. How do I disable dynamic updates under BIND 9 (named) for any zone?
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Linux Disable / Remove All NFS Services

NFS was not designed with security in mind, and has a number of weaknesses, both in terms of the protocol itself and because any NFS installation must expose several daemons, running on both servers and clients, to network attack. I use my CentOS based server only to server web pages and nothing else. How do I disable NFS services under RHEL / CentOS / Fedora Linux?
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CentOS / RHEL Configure Yum Automatic Update Retrieval and Installation

The yum command line tool is used to install and update software packages under RHEL / CentOS Linux server. I know how to apply updates using yum update command line, but I'd like to use cron to manually update packages where appropriate. How do I configure yum to install software patches / updates automatically with cron?
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SSH Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys2

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 server /var/log/secure file:

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

How do I fix this problem?
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Access Any Remote Server Port Without Modifying Firewall Settings

Q. I've couple of remote servers and I'd like to access few admin only application running on port 10000 and 3001. My firewall only allows port 80, 443, 25, 22 and 110 for public access. Do I need to open port 10000 and 3001 for everyone using firewall? How do I access my admin only apps without opening port 10000 and 3001?
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Linux Restart IMAP Services ( dovecot IMAP server )

How do I restart dovecot IMAP4 / IMAP (Internet Message Access Protocol) under RHEL / CentOS / Fedora / Debian / Ubutnu Linux?
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How To Restart Linux NFS Server Properly When Network Become Unavailable

How do I restart NFS server when network link goes down between two servers or NFS client / server under CentOS 4.x / RHEL / CentOS Linux 5.x?
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Linux: Tune NFS Performance

What values can be tuned to improve NFS performance? How do I improve my client performance under Linux operating systems?
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Edit DNS Configuration Files

Q. How do I edit dns configuration file to add my ISPs nameservers?
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