Frequent Questions
19,167 questions
634
votes
13
answers
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views
How do I deal with a compromised server?
This is a Canonical Question about Server Security - Responding to Breach Events (Hacking)
See Also:
Tips for Securing a LAMP Server
Reinstall after a Root Compromise?
Canonical Version
...
- 6,440
46
votes
5
answers
28k
views
Can you help me with my software licensing issue?
This is a Canonical Question about Licensing.
Questions on licensing are off-topic on Server Fault.
If your question has been closed as a duplicate of this question, then this is because we want to ...
- 12k
144
votes
4
answers
46k
views
Can you help me with my capacity planning?
This is a canonical question about capacity planning
Related:
How do you do load testing and capacity planning for web sites?
How do you do load testing and capacity planning for databases?
I have a ...
- 80.7k
285
votes
5
answers
119k
views
Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask
This is a Canonical Question about Apache's mod_rewrite.
Changing a request URL or redirecting users to a different URL than the one they originally requested is done using mod_rewrite. This includes ...
- 85.6k
405
votes
7
answers
1.0m
views
Why is my crontab not working, and how can I troubleshoot it?
This is a Canonical Question about using cron & crontab.
You have been directed here because the community is fairly sure that the answer to your question can be found below. If your question is ...
- 4,461
476
votes
8
answers
193k
views
How does IPv4 Subnetting Work?
This is a Canonical Question about IPv4 Subnets.
Related:
How does IPv6 subnetting work and how does it differ from IPv4 subnetting?
How does Subnetting Work, and How do you do it by ...
101
votes
8
answers
202k
views
How to send emails and avoid them being classified as spam?
This is a canonical question about how to handle email sent from your server being misclassified as spam. For additional information you may find these similar questions helpful:
Best ...
- 1,885
125
votes
5
answers
78k
views
How do you do load testing and capacity planning for web sites?
This is a canonical question about capacity planning for web sites.
Related:
Can you help me with my capacity planning?
How do you do load testing and capacity planning for databases?
What are some ...
- 12k
192
votes
5
answers
31k
views
I am under DDoS. What can I do?
This is a Canonical Question about DoS and DDoS mitigation.
I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all ...
- 25.6k
168
votes
3
answers
1.0m
views
What causes the 'Connection Refused' message?
This is a Canonical Question about Connection Refused
We see a lot of questions to the effect
When I try to connect to a system I get a message
Connection refused
Why is this ?
- 117k
186
votes
73
answers
249k
views
What tool do you use to monitor your servers?
For a more comprehensive list of monitoring tools and their features, check out this Wikipedia page.
As the question states, what are the most commonly used tools used for this task and what are their ...
193
votes
2
answers
49k
views
What are the different widely used RAID levels and when should I consider them?
This is a Canonical Question about RAID levels.
What are:
the RAID levels typically used (including the RAID-Z family)?
deployments are they commonly found in?
benefits and pitfalls of each?
- 101k
61
votes
2
answers
25k
views
What are SPF records, and how do I configure them?
This is a canonical question about setting up SPF records.
I have an office with many computers that share a single external ip (I'm unsure if the address is static or dynamic). Each computer ...
- 769
111
votes
6
answers
68k
views
Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?
This is a Canonical Question about Fighting Spam.
Also related:
How to stop people from using my domain to send spam?
What are SPF records, and how do I configure them?
There are so ...
- 78.4k
376
votes
6
answers
600k
views
What permissions should my website files/folders have on a Linux webserver?
This is a Canonical Question about File Permissions on a Linux web server.
I have a Linux web server running Apache2 that hosts several websites. Each website has its own folder in /var/www/.
/var/...
- 13.7k