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1500 questions
80
votes
8 answers
What should I do when I got the KEYEXPIRED error message after an apt-get update?
While updating my packages on a debian based system by a
sudo apt-get update
I've got that error message :
Reading package lists... Done
W: GPG error: ftp://ftp.fr.debian.org stable/non-US Release:
The following signatures were invalid:…
paulgreg
- 4,164
80
votes
11 answers
Multiple data centers and HTTP traffic: DNS Round Robin is the ONLY way to assure instant fail-over?
Multiple A records pointing to the same domain seem to be used almost exclusively to implement DNS Round Robin as a cheap load balancing technique.
The usual warning against DNS RR is that it is not good for high availability. When 1 IP goes down…
Valentino Miazzo
- 1,113
80
votes
6 answers
How to test if my server is vulnerable to the ShellShock bug?
How can I ensure my Bash installation is not vulnerable to the ShellShock bug anymore after the updates?
gtirloni
- 5,795
80
votes
6 answers
Centos 7 save iptables settings
Problem: iptables resets to default settings after server reboot.
I'm trying to set rule like this:
iptables -I INPUT -p tcp --dport 3000 -j ACCEPT
after that I do:
service iptables save
and it writes back something like this
iptables: Saving…
user1463822
- 903
80
votes
3 answers
php5-fpm: server reached pm.max_children
I have Nginx + php5-fpm. Several times per hour my website stucks and in logfile I see the following:
WARNING: [pool www] server reached pm.max_children setting (5),
consider raising it.
/etc/php5/fpm/pool.d/www.conf file contains the following…
user1821484
- 1,189
80
votes
11 answers
Private IP address in public DNS
We have an SMTP only mail server behind a firewall which will have a public A record of mail.. The only way to access this mail server is from another server behind the same firewall. We do not run our own private DNS server.
Is it a good idea to…
Geoff Dalgas
- 2,516
- 5
- 31
- 32
80
votes
3 answers
How long does negative DNS caching typically last?
If a DNS server looks up a record and it's missing, it will often "negatively cache" the fact that this record is missing, and not try to look it up again for a while. I don't see anything in the RFC about the TTL on negative caching should be, so…
Leopd
- 1,907
- 4
- 25
- 30
80
votes
4 answers
How to keep the full path with rsync?
When backing up with rsync, How do I keep the full directory structure?
For example, the remote server is saturn, and I want to backup saturn's /home/udi/files/pictures to a local directory named backup.
I want to have (locally)…
Adam Matan
- 13,574
80
votes
11 answers
How can I create a location in nginx that works with AND without a trailing slash?
Right now I have this config:
location ~ ^/phpmyadmin/(.*)$
{
alias /home/phpmyadmin/$1;
}
However, if I visit www.mysite.com/phpmyadmin (note the lack of trailing slash), it won't find what I'm looking for a 404. I assume because I don't…
Rob
- 2,453
80
votes
4 answers
How to make wireshark filter POST-requests only?
How to make wireshark filter POST-requests only?
Ilya Smagin
- 903
80
votes
13 answers
How Often Do Windows Servers Need to be Restarted?
A little background: We have several Windows servers (2003, 2008) for our department. We're a division of IT so we manage our own servers. Of the four of us here I'm the only one with a slight amount of IT knowledge. (Note the "slight amount".) My…
Evan
- 919
80
votes
11 answers
Remove "www" and redirect to "https" with nginx
I want to create a rule in nginx that does two things:
Removes the "www." from the request URI
Redirects to "https" if the request URI is "http"
There are plenty of examples of how to do each of those things individually, but I can't figure out a…
Devin
- 923
- 1
- 8
- 8
80
votes
2 answers
nginx url rewriting: difference between break and last
I don't understand the difference between break and last (flags of rewrite). The documentation is rather abstruse. I've tried to switch between the two in some of my configs, but I couldn't spot any difference in behavior. Can someone please explain…
user39883
80
votes
2 answers
sudoers: how to disable requiretty per user
I don't want to comment out the line in /etc/sudoers:
Defaults requiretty
Instead, I only want a certain user not to require a tty.
How can this be done?
user27451
- 1,171
- 2
- 11
- 14
79
votes
11 answers
Allow SCP but not actual login using SSH
Is there any way to configure a user on a Linux box (Centos 5.2 in this case) so that they can use scp to retrieve files, but can't actually login to the server using SSH?
DrStalker
- 7,036