Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.

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puppet Could not find dependency

I have inherited a puppet server. It has a couple of dozen hosts under management and it is mostly working fine. When I say mostly there are a few hosts that fail when checking in: Error: Failed to ...
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1answer
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Ubuntu iptables logs not going to any log file

I am trying to put logs in iptables but I can not find any log in any file. Although when I run dmesg command, I can see the iptables entries. But the same entry doesn't go to any log file. Here is ...
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9 views

ipa users cannot sudo on some machines only, including the ipa server

I'm having trouble with freeipa on a few machines. It's been very frustrating to debug so far. Here's the details of the issue; How it manifests: The user can login just fine to any host, but on ...
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2answers
16 views

cron job executing script not writing to file

I have a server running AIDE, and a cron job that runs executes a bash script and sends an email alert out. It is still a WIP, but I can't get the script to run properly. When the script is executed, ...
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1answer
22 views

IPTABLES - IP Restricted Port Forwarding for RDP

I can't find an answered question for this problem. I have about 7 ranges of IP address i would like to allow to RDP(port 3389) to a a server within my network. My main router uses iptables and i ...
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1answer
383 views

Using my IPs on OVH server via GRE

I can't route my IPs into a OVH server, can you help me to find the problem? Mikrotik GRE IP: 192.168.55.10 OVH Server GRE IP: 192.168.55.20 GRE iface name: ali1_fr1-ovz1 IP to route from Mikrotik to ...
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joint two conditions in bash script

Note: Update Jun 28 I have an iptables script .sh (bin/bash) with the rules: function run_ips(){ for ip in $(sed '/#.*/d' ips.txt); do if echo $ip | grep -q "-" >/dev/null; then iptables -A ...
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How to see on Linux what network interface and source IP address is used for a route to a specific destination host?

If I have multiple network interfaces (here: 2) on a Linux machine (here: Debian Lenny). How do I see, over what network interface (NIC) a route to a specific destination host is going and what source ...
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1answer
27 views

EXT4 filesystem corruption

I have a CentOS 6x server and running a Java application on it, the application is using a mount point /javapp which is an EXT4 filesystem. suddenly I got the following error in the system logs: ...
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4answers
3k views

Kill processes if high load average

Not so far ago LA on my server raised to 400 and I couldn't even login to server using ssh. Does exists any software, that can prevent this situations by automatically killing processes that making ...
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5answers
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Linux Command to find Strings in Binary or non ascii file

Is there any linux command to extracts all the ascii strings from an executable or other binary file? I suppose I could do it with a grep, but I remember hearing somewhere that such a command existed?
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How to configure PHP CLI on linux ubuntu to run as www-data?

I have a symfony2 application on my ubuntu. Symfony has a plenty of useful console commands (like php app/console cache:clear or php app/console assets:install web). The problem is If I run them as ...
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2answers
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When is fsck dangerous?

Recently I've seen the root filesystem of a machine in a remote datacenter get remounted read-only, as a result of consistency issues. On reboot, this error was shown: UNEXPECTED INCONSISTENCY: RUN ...
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2answers
1k views

Ubuntu server closing connection after successful login

I am unable to logon to my Ubuntu (12.04 LTS) server via WinSCP or sftp. There was previously a permission problem for ssh_host_* files in /etc/ssh. This was after I tried chmod -R from another ...
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0answers
25 views

chown: Operation not permitted for root on ext4 root-partition

After upgrading from Ubuntu v14.04 to v16.04 chown doesn't seem to work any longer on my server. I checked following: filesystem is RW user exists folder is not immutable all commands executed as ...
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2answers
2k views

Netstat count TIME_WAIT connections by port

I can obtain individual TIME_WAIT counts on a port, netstat -nat | grep :11300 | grep TIME_WAIT | wc -l; but how to do this based on all ports eg: 11300 2900 connection 3306 1200 connection ...
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4 views

Server load balancing apache2 and python multiprocessing job

I have a VM that has two things to do, one is building (python script, multiprocessing) a key-value pairs and write results to redis within the same machine. Same machine also serves as my webserver,...
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3answers
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How to test disk latency on Linux?

Made an upgrade of RAID firmware and latency as it seems have increased. Could you please advise on the most accurate way to examine disk read and write latencies?
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1answer
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Multiple Reverse SSH Tunnels using Single Port

I am able to accept reverse SSH connections from multiple remote systems on a single server using a port for each connection: Remote A: ssh -fN -R5000:localhost:22 user@server-ip -p22 Remote B: ssh -...
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1answer
17 views

DH GEX group out of range

I'm having a sudden issue SSHing into my server: ssh -v --@-- OpenSSH_7.2p2 Ubuntu-4ubuntu1, OpenSSL 1.0.2g-fips 1 Mar 2016 debug1: Reading configuration data /home/paul/.ssh/config debug1: Reading ...
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9 views

Difference between ldap/ldap.conf and Samba4 smb.conf [on hold]

I have been using using Samba4 as domain controller, with active directory authentication for different services for a couple of weeks. I am wonder what is the difference between the CA which I can ...
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1answer
13 views

MySQL won't allow login from normal user account

When connecting to MySQL as root from the linux user user user@computer:~/$ mysql -u root -p Enter password: ERROR 1698 (28000): Access denied for user 'root'@'localhost' When doing the same exact ...
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2answers
30 views

What does the sendmail daemon do exactly when it receives a kill -15 (SIGTERM) request? How does this affect messages that are in transit?

Can someone elaborate on what would happen if the sendmail daemon is in the middle of processing a message when it receives a kill -15 request? Would it finish processing whatever message it's working ...
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1answer
1k views

Intermittent NFS lockups on Isilon cluster

We have an Isilon cluster with 8 IQ 12000x nodes which exports storage via several NFS shares for a handful of Linux and Solaris clients. There is a Linux system that has one of these NFS filesystems ...
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1answer
14 views

AWS Cloudformation: Invalid template resource property error

I am attempting to create a Cloudformation template to configure an IAM role. As far as I can tell my JSON is 100% valid but apparently I'm overlooking something else because it's not able to be ...
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8answers
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Why would a server not send a SYN/ACK packet in response to a SYN packet

Lately, we've become aware of a TCP connection issue that is mostly limited to mac and Linux users who browse our websites. From the user perspective, it presents itself as a really long connection ...
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11 views

Restrict access to Linux via PAM with configured SSO

i have SLES 12 in Active Directory Domain. Single Sign On for SSH is configured. I want to allow access to server only to some AD groups via PAM (not only for SSH Service, ftp, etc.). I tried to add ...
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16 views

Unkown File permissions for /etc/resolv.conf

I am unable to ping any url (for example www.google.com), neither any of the website is working. However, I can ping static IPs (E.g. 8.8.8.8). A little debugging showed that the issue is /etc/resolv....
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25 views

Openvpn tap interface configuration gets self assigned IP

I have a strange misconfiguration on my openvpn tap network. Clients can connect and get there IP address in 192.168.42.x as intended, but after few seconds another address gets assigned to it, self-...
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2answers
2k views

Adding a new user into linux from a script

I am using a customized Redmine installation to manage projects. I have managed to hook the addition of new users and send the login information to a bash script I have. Below is my script: #!/bin/sh ...
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2answers
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postfix/dovecot says “postmaster_address setting not given” but it is

I'm trying to configure postfix and dovecot to work together with virtual domains stored in MySQL, but I keep running into this whenever mail is passed from postfix to dovecot. Apr 26 11:54:40 smtp ...
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1answer
17 views

sudo-like privilege management for docker containers

I want to allow a Docker container to invoke some actions on another container without granting it full privileges. An example would be a Docker container which does log rotation and reloads the ...
13
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5answers
28k views

dd on entire disk, but do not want empty portion

I have a disk, say /dev/sda. Here is fdisk -l: Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (...
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2answers
1k views

Traceroute doesn't reach gateway

i have problem with my opensuse 11.3 network. So, i've assigned ip 192.168.137.2 to it, and another computer (win7) with ip 192.168.137.1 On the opensuse, the gateway is the 192.168.137.1. and the ...
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1answer
66 views

how to make a VMware clone into a running instance from the command line?

I am using VMkfstools and the vim-cmd suite of programs to clone Linux hosts. I'm trying to figure out how to turn a clone into a new running instance, but for some reason I'm not locating any ...
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1answer
3k views

How to get OpenVPN Client (Mikrotik RouterOS) <-> OpenVPN server (Debian/Linux) setup to work

I have some issues with making MT to work with OpenVPN server (Debian). I can make successfull connection to OVPN server, but traffic is not routed through OVPN server. Here is my configuration. ...
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4answers
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Is there a way to list all configurable `alternatives` (symlinks for similar commands) on the system?

The alternatives command (package chkconfig) on RHEL manages symlinks which link a generic name to one of the alternative implementations. For example, mta group of symlinks can be provided by ...
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20 views

postfix mails stuck in mailqueue

I ran into a problem, I'm trying to set up postfix mail server (I'm using webmin), everything seems to work fine, I successfully connected outlook to POP3/SMTP, but as soon as I send an email, it gets ...
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2answers
21 views

Unable to install asterisk-core on centos x86_64 [on hold]

I try to install on a linux Centos x86_64 a library named asterisk-core-11.20.0-1_centos6.x86_64 which not found the library libsrtp.so.0 present at the path /usr/lib/64. the error is: Error: Package:...
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2answers
5k views

du command takes WAY too long to run

I am running du -sh in a variety of directories to find disk hogs. I got two identical servers (Dell PE2850s), both with RHEL5 and it will take significantly longer to run du on one server over the ...
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Linux iptables to forward all traffic from one port to another ip [on hold]

I want to make so that iptables forwards all traffic from port 65535 to the LAN IP 10.8.0.2 How would I do that? I've tried these but they don't seem to work. iptables -t nat -I PREROUTING -i tun1 -...
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2answers
4k views

WMI: wmic linux agent query error: NTSTATUS: NT_STATUS_ACCESS_DENIED

Myself new to wmic and keep trying for a long time with default agent query approach. wmic is linux based WMI tool to talk to windows WMI agent. While trying to fetch data with wmic from nt(win7 with ...
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4answers
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In Puppet, how would I secure a password variable (in this case a MySQL password)?

I am using Puppet to provision MySQL with a parameterised class: class mysql::server( $password ) { package { 'mysql-server': ensure => installed } package { 'mysql': ensure => ...
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1answer
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How to forward specific packets from a machine to another machine? [on hold]

I have a network with 3 linux hosts, A, B, and C. I want to send 1,000 packets from A to B, and B should automatically forward it to C. How should I do it? B has one adapter with IP 192.168.1.100/24 ...
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1answer
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Gmail is blocking emails from my mail server ( Postfix ) CentOS 6

I'm unable to send emails from my mail server. I've tried every single possible solution I came across. Firstly, I WAS ABLE to send emails but they were going to spam so I decided to install OpenDKIM ...
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OpenVPN server to forward traffic to client

I've set up OpenVPN on my Debian server. I want all traffic that goes on the OpenVPN server on port 65535 to route to a client's port. The client is connected to the server using OpenVPN. But the ...
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1answer
4k views

Fresh Proxmox VE 2.1 installation with defaults can't be reached or pinged

I am using the lastest Proxmox VE 2.1. My server has two NICS with a uplink only connected into eth0. My Server is a co-located server utilizing public IPv4 IPs. It is not behind a firewall or any ...
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1answer
9 views

using umask to set default file settings [duplicate]

I am setting default umask of linux box for the first time. I log in as root user on a Centos 6 server. I want these default values: owner: read/execute/write (7) group: read/execute (5) other: ...
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6 views

Force nproc ulimit on non interactive user

I have a script that can be launched n times at the same time through php-fpm. php-fpm pool is set to run under a certain username and I want to limit the number of processes this username can launch. ...
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28 views

Outgoing spam from postfix using my domains

I get a lot of spam outgoing from my server which uses fake emails but real domains (that are hosted on my server Linux Debian Squeeze). These all have "msg" plus a random number as Email address. ...