Most Popular
1500 questions
191
votes
6 answers
How do I convert a .cer certificate to .pem?
I have a .cer certificate and I would like to convert it to the .pem format.
If I remember correctly, I used to be able to convert them by exporting the .cer in Base64, then renaming the file to .pem .
How do I convert a .cer certificate to .pem?
systempuntoout
- 2,055
- 2
- 13
- 10
190
votes
5 answers
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 100Mbps of my available bandwidth. Nobody can…
Falcon Momot
- 25,244
- 15
- 63
- 92
190
votes
4 answers
Should I quit using Ifconfig?
With the servers that mount Infiniband cards, when I use the ifconfig command, I get this warning:
Ifconfig uses the ioctl access method to get the full address
information, which limits hardware addresses to 8 bytes.
Because Infiniband address has…
Zhen
- 2,159
- 4
- 19
- 31
190
votes
2 answers
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?
MDMarra
- 100,734
- 32
- 197
- 329
189
votes
12 answers
Physically locating the server
I've got a CentOS server somewhere in the building; I can login into it remotely and VNC, etc. Now I've got to physically move it, and for that I need to physically locate the machine among the lookalikes around the office.
What can I do remotely to…
Michael
- 1,723
- 2
- 11
- 7
189
votes
9 answers
Resolve host name from IP address
I'm looking for a command line tool which gets an IP address and returns the host name, for Windows.
DouglasJose
- 2,013
- 2
- 14
- 7
188
votes
6 answers
SSL Certificate Location on UNIX/Linux
Is there any standard or convention for where SSL certificates and associated private keys should go on the UNIX/Linux filesystem?
John Topley
- 2,175
- 3
- 16
- 17
188
votes
5 answers
DNS - NSLOOKUP what is the meaning of the non-authoritative answer?
For some domains nslookup gives me a Non-authoritative answer section. What does this mean?
Got answer:
HEADER:
opcode = QUERY, id = 3, rcode = NXDOMAIN
header flags: response, want recursion, recursion avail.
questions…
mahen3d
- 4,342
- 14
- 36
- 57
187
votes
73 answers
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 strengths and weaknesses?
Aron Rotteveel
- 8,449
- 17
- 53
- 64
187
votes
13 answers
Why couldn't MAC addresses be used instead of IPv4|6 for networking?
I am reading up on TCP/IP and other related protocols and technologies. MAC addresses are described as being (reasonably :) unique, and as having a large possibility space (several hundred trillions), while also being assigned to all network…
Félix Saparelli
- 1,393
- 2
- 10
- 10
185
votes
6 answers
185
votes
10 answers
How do I verify the speed of my NIC?
I just installed a new gigabit network interface card (NIC) in Linux. How do I tell if it is really set to gigabit speeds? I see ethtool has an option to set the speed, but I can't seem to figure out how to report its current speed.
User1
- 2,486
- 5
- 20
- 21
185
votes
14 answers
How to create a UUID in bash?
In Java it is possible to create a random UUID:
UUID uuid = UUID.randomUUID();
How to do this in Bash?
raoulsson
- 4,763
- 10
- 34
- 29
184
votes
61 answers
Good tools that fit on a thumb drive
I have been on the lookout lately for some good tools to fill up my flash drive and I thought I would ask the Server Fault community for recommendations on good tools that will fit onto a thumb drive.
Some I use are Driver Packs, CCleaner and the…
Shard
- 1,432
- 4
- 21
- 35
183
votes
16 answers
Why is DNS failover not recommended?
From reading, it seems like DNS failover is not recommended just because DNS wasn't designed for it. But if you have two webservers on different subnets hosting redundant content, what other methods are there to ensure that all traffic gets routed…
Lin
- 2,909
- 7
- 27
- 25