These are the questions we have identified as Canonical:
Capacity Planning
- Generic Capacity Planning: Can you help me with my capacity planning?
- How do you do load testing and capacity planning for databases?
- How do you do load testing and capacity planning for web sites?
Career
- Starting out: What a beginner should know/learn for sysadmin job?
Datacenter Design
- What's the best fire suppression for a server room?
- Server room survival kit?
- What were your server room pain points, big wins and must haves?
- What to look for in a datacentre ethernet switch
Documentation
EMail & Spam
- How to stop people from using my domain to send spam?
- What are SPF records, and how do I configure them?
- Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?
- Prevent mail being marked as spam
- How to send emails and avoid them being classified as spam?
Hardware
- Why is Enterprise Storage so expensive?
- What are the different widely used RAID levels and when should I consider them?
- What is a Storage Area Network, and which benefits does it have over different storage solutions?
- Rack Mount Servers - Build them or Buy them?
Hosting provider/server hardware shopping
- Dedicated server or Cloud Hosting?
- Use Google Apps/Cloud Services as a Domain Controller Replacement
Infrastructure Software
Active Directory
- What is Active Directory Domain Services and how does it work?
- What is Group Policy and how does it work?
- What should the order of DNS servers be for an AD Domain Controller and Why?
DNS
- Should we host our own nameservers?
- How long does it take for DNS records to propagate?
- What is a glue record?
- How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port
- Why does DNS work the way it does?
- Do internet standards require reverse DNS for every device?
- Is dig +trace always accurate?
- What is the role of NS records at the apex of a DNS domain?
- Why can't a CNAME record be used at the apex (aka root) of a domain?
- How do I understand my CPU usage on a DNS server?
- How can I manage all of my domains with minimal configuration?
- Why is geo-redundant DNS necessary for small sites?
- How do I set up a "secure" open resolver?
Licensing
- Can you help me with my software licensing issue?
- Do I need a RHEL subscription to install packages?
Networking
- Networking Units: Not getting expected performance from 100Mb Ethernet
- Loopback to forwarded Public IP address from local network - Hairpin NAT
- What tools can create a map of my network?
- What am I looking for in a Monitoring Solution?
- How does IPv4 Subnetting Work?
- How does IPv6 subnetting work and how does it differ from IPv4 subnetting?
- Switching to IPv6 implies dropping NAT. Is that a good thing?
- How do VLANs work?
- Exposing multiple servers behind NAT using a single public IP address
- Connecting to a remote server through a VPN when the local network subnet address conflicts with a remote network
- What causes the 'Connection Refused' message?
General Unix/Linux OS Stuff
- Why is Linux reporting "free" memory strangely?
- Why is my crontab not working, and how can I troubleshoot it?
- Unix Server Partitioning & Filesystem Layout
- Install software from packages, or build it from source?
- Can you help me with my software dependency issue?
- Installing a third party application package on CentOS 6.4 fails due to missing dependencies libcrypto.so.10 and libssl.so.10
- Why drop caches in Linux?
Security
- Heartbleed: What is it and what are options to mitigate it?
- How do I deal with a compromised server?
- What permissions should my website files/folders have on a Linux webserver?
- What should I do about a "misbehaving" user?
- Restricted Shell: How to restrict the users' shell allowing to execute shell programs
- How to convince a big boss that he does not need administrator privileges?
- Tips for Securing a LAMP Server
- How do I deal with the removal/eradication of an unknown worm on our network?
- Why is "chmod -R 777 /" destructive?
- I am under DDoS. What can I do?
SSH
- Does getting disconnected from an SSH session kill your programs?
- ProxyCommand: How to configure a shortcut for an SSH connection through a SSH tunnel
Terminal Server (RDS)
Uptime
Virtualization
Web Servers
- mod_rewrite: Everything you wanted to know about mod_rewrite rules but were afraid to ask
- Picking the right MPM (on *NIX systems): How do I select which Apache MPM to use?
- One-click (x)AMP: Why not use a WAMP stack?, Meta: What to do with XAMPP/MAMP/WAMP questions
- IIS7: What are the differences between Websites, Directories, Virual Directories, and Applications in IIS 7?
- SNI: Multiple SSL domains on the same IP address and same port?
- Host Header vs. DNS: How does pointing a CNAME on my domain to a service-provider's server enable them to offer customized services?
Windows (General)
- Host files: Hosts file ignored, how to troubleshoot
