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1500 questions
79
votes
4 answers

What is the difference between PV and HVM virtualization types in ec2?

AWS EC2 offers two types of virtualization of Ubuntu Linux EC2 machines - PV and HVM. PV: HVM: What is the difference between these types?
Adam Matan
  • 14,084
79
votes
8 answers

Is STARTTLS less safe than TLS/SSL?

In Thunderbird (and I assume in many other clients, too) I have the option to choose between "SSL/TLS" and "STARTTLS". As far as I understand it, "STARTTLS" means in simple words "encrypt if both ends support TLS, otherwise don't encrypt the…
Foo Bar
  • 939
79
votes
4 answers

How do I connect to ssh with a different public key?

I have two public keys, one for some servers and one for others. How do I specify which key to use when connecting to a server?
rid
  • 1,000
79
votes
3 answers

What is the difference between a hostname and a fully qualified domain name?

I am new to the world of setting up servers and am baffled by the term hostname and fully qualified domain name (FQDN). For example, if I want to set up a server that hosts files on the local network i.e. a file server, what would I use a hostname…
79
votes
5 answers

Is Postfix the same thing as Sendmail?

I have Postfix setup on my server so that I can send outgoing mail using the command-line: mail -s "Subject" address@example.com Is this using Sendmail or Postfix ? Is "Sendmail" just a software category or a distinct program ? If something is…
Xeoncross
  • 4,709
79
votes
5 answers

How to properly set permissions for NFS folder? Permission denied on mounting end.

I'm trying to connect to an NFS folder on my dev server. The owner of the folder on the dev server is darren and group darren. When I export and mount it to my Mac using the Disk Utility it mounts, but then when I try to open the folder is says I do…
Darren
  • 1,027
79
votes
1 answer

What is the difference between a Source NAT, Destination NAT and Masquerading?

What is the difference between a Source NAT, Destination NAT and Masquerading? For example, I thought IP Masqurading was what they used to call it in Linux? But what confuses me is that in our Astaro firewall there is IP Masquarading as well as NAT…
hookenz
  • 14,848
78
votes
9 answers

What is the debian-sys-maint MySQL user (and more)?

I have been bitten several times by the 'debian-sys-maint' user that is installed by default on the mysql-server packages installed from the Ubuntu repositories. Generally what happens is I pull a fresh copy of our production database (which is not…
Joe Holloway
  • 1,969
78
votes
3 answers

How to use docker secrets without a swarm cluster?

Currently we im a running application on a single docker container, the application needs all sorts of sensitive data to be passed as environments variables, Im putting those on the run command so they don't end up in the image and then on a…
78
votes
9 answers

Securely add a host (e.g. GitHub) to the SSH known_hosts file

How can I add a host key to the SSH known_hosts file securely? I'm setting up a development machine, and I want to (e.g.) prevent git from prompting when I clone a repository from github.com using SSH. I know that I can use StrictHostKeyChecking=no…
78
votes
2 answers

Create a directory under /var/run at boot

I had a daemon that needed its own dir in /var/run for its PID file with write permission granted to the daemon's user. I found I could create this dir with these commands: # mkdir /var/run/mydaemon Then I could change its ownership to the…
user24601
  • 1,043
78
votes
4 answers

SSH key authentication using LDAP

In short: Would like a way to do SSH key authentication via LDAP. Problem: We use LDAP (slapd) for directory services and we've recently moved to using our own AMI for building instances. The reason the AMI bit is important is that, ideally, we…
c4urself
  • 5,880
78
votes
3 answers

nginx: Log complete request / response with all headers?

We have an application server that sometimes hangs. We suspect it is due to a bad request from a client. Can nginx log the complete request/response (like fiddler captures) to files, so we can see the requests that were sent before the hang? (We…
78
votes
10 answers

Can I specify a port in an entry in my /etc/hosts on OS X?

Possible Duplicate: How to use DNS to redirect domain to specific port on my server I want to trick my browser into going to localhost:3000 instead of xyz.com. I went into /etc/hosts on OS X 10.5 and added the following entry: 127.0.0.1:3000…
Tony
  • 4,393
78
votes
4 answers

Temporarily disable ssh public key authentication from client

Is there a way to temporarily disable public key authentication when ssh'ing, and use password authentication instead? I currently want to access remote server, but I'm using another laptop, not mine. Browsing that link, I found that the command ssh…
Nsukami _
  • 891