Greatest Hits
56
votes
4
answers
225k
views
DIMMs: Single vs. Double vs. Quad Rank
What difference does the 'Rank' of DIMMs make to server memory? For example, when looking at server configurations I see the following being offered for the same server:
2GB (1x2GB) Single Rank PC3-...
- 39.7k
31
votes
7
answers
165k
views
How to monitor the hard disk status behind Dell PERC H710 Raid Controller with CentOS 6?
I have a Dell server running CentOS 6 using PERC H710 Raid Controller card with Raid 5 setup and I want to monitor the hard disk failure/working status behind the Raid Controller.
Then I should be ...
- 685
57
votes
6
answers
177k
views
How to configure basic authentication in Apache httpd virtual hosts?
I'm trying to configure mercurial access using Apache http.
It requires authentication. My /etc/apache2/sites-enabled/mercurial looks like this:
NameVirtualHost *:8080
<VirtualHost *:8080>
...
- 4,755
7
votes
3
answers
104k
views
Error when running docker build on any dockerfile: "unable to prepare context: unable to evaluate symlinks in Dockerfile path"
I'm running :
$ docker build -t somefile .
Every time I run that I get this error:
unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat
The full error is:
unable to ...
- 181
10
votes
3
answers
55k
views
How do I specify a port other than 80 when adding SSL certificate using Certbot?
I have a server which runs 2 different web servers (Apache and Nginx). The Apache server takes care of all the traffic directed to Wordpress sites whereas the Nginx server serves my Python API and ...
28
votes
9
answers
173k
views
How do I get Centos VM to re-read its increased Disk size WITHOUT a reboot
I have a CentOS 5 VM and I've just increased the VM disk from 10G to 20G, but I cannot get fdisk to see the new disk size without a reboot.
I've tried echo 1 > /sys/block/sda/device/rescan, it ...
- 968
56
votes
1
answer
171k
views
What's the difference between sudo su - postgres and sudo -u postgres?
PostgreSQL users peer authentication on unix sockets by default, where the unix user must be the same as the PostgreSQL user. So people frequently use su or sudo to become the postgres superuser.
I ...
- 11.2k
35
votes
2
answers
208k
views
Enabling mod_headers on apache2
I am trying to enable the module "headers" into my apache2 installation on ubuntu 10.04 system, here's some info:
Server version: Apache/2.2.14 (Ubuntu)
When I run the command:
a2enmod ...
- 866
17
votes
4
answers
107k
views
How To Disable diffie-hellman-group1-sha1 for SSH
I have found that my server via SSH still supports diffie-hellman-group1-sha1. To stay compliant with latest PCI Compliance I have been trying to figure out how to disable diffie-hellman-group1-sha1. ...
- 273
99
votes
17
answers
88k
views
Does drilling a hole into a hard drive suffice to make its data unrecoverable?
We have a lot of PCs in the company and nobody wants to wipe a multitude of hard drives. We also have many apprentice toolmakers who really want to destroy things. Thus, every couple of months, our ...
- 931
60
votes
6
answers
112k
views
"reboot" or "shutdown -r now": what restart command is safer?
We have in our organization around ~500 RedHat Linux machines.
On all the machines we installed applications and services under /etc/init.d, and oracle RAC servers. We intend to perform yum updates ...
- 1,081
82
votes
5
answers
165k
views
Best location to keep SSL certificates and private keys on Ubuntu servers?
On Ubuntu, it looks like the best place for a private key used to sign a certificate (for use by nginx) is in /etc/ssl/private/
This answer adds that the certificate should go in /etc/ssl/certs/ but ...
- 1,687
16
votes
3
answers
197k
views
What does "Default Server: Unknown" mean for Windows nslookup
I'd like to solve a question with your kind help, about nslookup on Windows. Please see my CMD commands below(run on WinXP SP2).
C:\>ipconfig /all
Windows IP Configuration
Host Name . . ....
- 1,759
20
votes
4
answers
162k
views
How can I list the Active Directory user attributes from a linux computer?
How can I list the Active directory user attributes from a Linux computer?
The Linux computer is already joined to the domain. I can use 'getent' to get the user and group information, but it does ...
- 741
15
votes
5
answers
111k
views
Wireshark is not showing my network interface?
I want to capture traffic on Ethernet 4 but you can see that Ethernet 4 is not present in Wireshark network interface though Ethernet 4 is present in Networking and sharing center.
Screenshot of ...
- 249
22
votes
3
answers
174k
views
How do I use curl in a cron job?
I need to set up a cron job in cpanel that calls a URL (on the same server) once a week. I was going to use wget but it turns out this is disabled on the shared server being used.
Is there an ...
- 335
32
votes
4
answers
192k
views
How to troubleshoot connectivity when curl gets an *empty response*
I want to know how to proceed in troubleshooting why a curl request to a webserver doesn't work. I'm not looking for help that would be dependent upon my environment, I just want to know how to ...
- 439
43
votes
2
answers
110k
views
Can not get rid of `net::ERR_CERT_COMMON_NAME_INVALID` error in chrome with self-signed certificates
There are numerous question on the web where people are having difficulty setting up self signed certificates for use on internal network.
Just to link a few:
Getting Chrome to accept self-signed ...
- 535
44
votes
2
answers
38k
views
Does Apache Webserver use log4j (CVE-2021-44228)?
Does the apache webserver (apache2) use log4j?
I have Apache2 2.4.38 (debian) installed on Raspberry Pi OS (64bit) and found some strange records in my log regarding CVE-2021-44228 from kryptoslogic-...
- 523
62
votes
1
answer
146k
views
What does "Connection: close" mean when used in the response message?
When the client uses the Connection: close header in the request message, this means that it wants the server to close the connection after sending the response message.
I thought that this header is ...
- 623
24
votes
8
answers
179k
views
How to backup virtual machines on a standalone ESXi host?
Standalone ESXi (4.1) host without any vCenter Server.
How to backup virtual machines as quickly and storage-friendly as possible?
I know I can access the ESXi console and use the standard Unix cp ...
- 71.3k
5
votes
1
answer
99k
views
How to change permission of a folder to 777 in Dockerfile?
I have a project directory like this:
|-var/www
|-docker-compose.yml
|-app
|--uploads
|---photos
|-Dockerfile
This is my docker-compose.yml file:
myapp:
build:
context: myfolder
...
- 153
18
votes
9
answers
159k
views
RDP exits immediately after connecting to Windows Server 2008 R2
Background: I recently got a Windows cloud VPS server. I don't have much experience with server admin (I'm a programmer), and what little I do have is with linux servers.
Ever since getting the ...
- 1,065
40
votes
2
answers
143k
views
In LDAP, what exactly IS a bind DN?
I've written various pieces of code that connect to LDAP servers and run queries, but it's always been voodoo to me. One thing I don't really understand is the concept of a bind DN. Here's an example ...
- 1,631
21
votes
6
answers
108k
views
Redis not starting with systemctl
I have installed redis on an ubuntu 16.04 machine and if I run /usr/local/bin/redis-server /etc/redis/cluster/7000/redis.conf it starts up and I can connect to it without issues.
However I want to ...
- 383
12
votes
8
answers
80k
views
Vgextend : "device excluded by a filter"
I am at a new internship and I am asked to extend a volume group, seemed fine :
vgextend [my_group] /dev/sdb
But now I get an error message telling me :
Device /dev/sdb excluded by a filter`
...
- 123
64
votes
5
answers
122k
views
Optimal value for Nginx worker_connections
Nginx worker_connections "sets the maximum number of simultaneous connections that can be opened by a worker process. This number includes all connections (e.g. connections with proxied servers, among ...
- 719
35
votes
2
answers
87k
views
What does `* Mark bundle as not supporting multiuse` mean in my curl trace?
When I do a curl -v to some docker container that I created, I get:
* Mark bundle as not supporting multiuse
What does it mean? Where is it documented?
- 465
44
votes
8
answers
162k
views
where are the default ulimit values set? (linux, centos)
I have two CentOS 5 servers with nearly identical specs. When I login and do ulimit -u, on one machine I get unlimited, and on the other I get 77824.
When I run a cron like:
* * * * * ulimit -u &...
- 441
9
votes
2
answers
118k
views
FileZilla Server 425 Can't open data connection for transfer of "/"
I am having difficulties connecting to my FileZilla Server via my FileZilla Client. When trying to connect to the local address while on the same network I am able to connect successfully though (so ...
- 320
4
votes
3
answers
80k
views
Failed to start MySQL Community Server
Following error is being showed while checking the status for my-sql .
OS: Ubuntu 18.04.3
Mysql: mysql Ver 14.14 Distrib 5.7.27, for Linux (x86_64) using EditLine wrapper
mysql.service - MySQL ...
- 145
10
votes
7
answers
90k
views
Nginx displaying failed (13: Permission denied) when trying to access new site
I am trying to set up my own web server to learn a bit more about server admin.
I have decided that I want to serve each sites files from a public_html folder inside the users /home directory.
I ...
- 259
105
votes
8
answers
220k
views
What limits the maximum number of connections on a Linux server?
What kernel parameter or other settings control the maximum number of TCP sockets that can be open on a Linux server? What are the tradeoffs of allowing more connections?
I noticed while load testing ...
- 2,396
19
votes
6
answers
103k
views
Can not access mysql docker
I am using docker-compose to create mysql container.
I get host IP 172.21.0.2.
But when I connect mysql. I get error:
My docker-compose.yml:
version: '2'
services:
### Mysql container
mysql:
...
- 193
6
votes
3
answers
23k
views
Ubuntu Server 22.04.1 LTS "failed to connect to https //changelogs.ubuntu.com/meta-release-lts. Check your Internet Connection or Proxy Settings"
When I logged in to my Ubuntu Server in VirtualBox this message appeared below "failed to connect to https //changelogs.ubuntu.com/meta-release-lts. Check your Internet Connection or Proxy ...
github
- 61
12
votes
7
answers
104k
views
How do I completely turn off Windows Defender from PowerShell?
Set-MpPreference -DisableRealtimeMonitoring disables the first one, what are the specific switches to disable the others you see when you open the UI? I have not found a clear example of this in the ...
- 4,253
116
votes
8
answers
171k
views
How to run command as user who has /usr/sbin/nologin as Shell?
All I need to do is to run a specific script as a particular user who does have the nologin/false shell indicated in /etc/passwd.
I would run the script as root and this should run as another user.
...
- 1,181
17
votes
5
answers
101k
views
Where are windows 10 defender offline scan logs/results?
I can't find any events or log files,
are there such records somewhere or WD reports only if it finds something?
Windows 10 pro,
drive is encrypted with bitlocker (might affects somehow?)
- 171
10
votes
4
answers
158k
views
openssl s_client shows alert certificate unknown but all server certificates appear to be verified
I am troubleshooting errors establishing a secure connection to an EPP server. I issue the command below and see that all of the server certificates are verified, but still I get an error (...
- 103
16
votes
3
answers
116k
views
safely upgrade glibc on CentOS 7
I've tried a python application on my CentOS machine and it gives me the following error:
ImportError: /usr/lib64/libc.so.6: version `GLIBC_2.18' not found (required by /tmp/_MEI2BYIr4/libstdc++.so.6)...
- 319
30
votes
7
answers
152k
views
How do I force NGINX to load new static files?
I recently pushed a major update to a site and I'm having an issue where some people can't log in because their browser is loading old javascript files. Some of the things I have done include:
Cache ...
- 778
21
votes
8
answers
201k
views
Cleaning up a server's C:\ drive. All known ways
I have a c:\ on a server that is filling up, most likely due to the accumulation of patches over the years.
I'm told by Microsoft PSS Support that it is unwise to simply delete the compressed ...
26
votes
4
answers
216k
views
What is the difference between SFTP port 22 or port 990?
I know that explicit "negotiated" FTPS is preferred, because it still uses the standard port 21 with that method but in regards to "implicit" non-negotiated FTPS using a standard port of 990 vs. port ...
- 4,200
52
votes
6
answers
60k
views
SSL for devices in local network
Initial question
We make devices which run a webserver and the user can control some functionality of the device by browsing directly to the IP of the device. This can be a fixed IP when a direct WiFi ...
- 621
9
votes
5
answers
63k
views
bash: dpkg-reconfigure: command not found
Debian10 seems to have removed the commands poweroff, reboot and dpkg-reconfigure, probably among others. What do I do instead of dpkg-reconfigure locales?
As a side note, I read the release notes ...
- 267
71
votes
7
answers
141k
views
What's the easiest way to make my old init script work in systemd?
I don't want to do the right thing by creating a new systemd script, I just want my old init script to work again now that I've upgraded my system to an OS that's using systemd.
I've briefly ...
- 1,090
10
votes
3
answers
92k
views
apt-key add on Debian Stretch: no valid OpenPGP data found
I'm trying to follow the installation instructions for Debian provided on Docker website. Unfortunately adding a GPG key fails for me:
$ curl -fsSL https://download.docker.com/linux/debian/gpg | apt-...
- 201
7
votes
4
answers
159k
views
MySQL remote connection - Access denied for user 'username'@'localhost' (using password: YES)
I am setting up a remote connection to a MySQL server but no matter what I try I am getting access denied error from the remote server.
I added the user by:
CREATE USER 'username'@'REMOTE_IP_ADDRESS'...
- 650
36
votes
3
answers
175k
views
How to Ping explicitly from eth1 instead of eth0
I'm trying to execute a ping with eth1, but the program uses eth0(the default network device). Any tips, tricks, or alternate techniques available?
- 371
24
votes
8
answers
171k
views
How to resolve FTP Error “Failed to retrieve directory listing” for Administrator account in IIS 7.5
Using my administrator account, I FTP connected to my IIS 7.5 FTP Site with FileZilla. I was able to successfully upload a file, but I keep getting a "Failed to retrieve directory listing" in ...
- 695