Author Archives: marskarthik

Enable SSH Root login in Linux

You need to edit /etc/ssh/sshd_config, and change PermitRootLogin to yes PermitRootLogin yes Also change StrictModes to no StrictModes no Then reload SSH: service ssh reload

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Enable root access in Ubuntu

To enable the Ubuntu root account, first we need to set up password for the root user. sudo passwd root Then unlock the root account sudo passwd -u root

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Server Hardening Linux Applications

OS Harden sysctl -w net.ipv4.ip_default_ttl=128 (changed it right then) and add net.ipv4.ip_default_ttl = 128 to /etc/sysctl.conf (so it applys at reboot) ______________________________________________________ APACHE AND PHP ServerSignature Off ServerTokens Prod ServerTokens Prod[uctOnly] Server sends (e.g.): Server: Apache ServerTokens Major Server sends … Continue reading

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Yum and Apt-Get Command Examples

Ubuntu Update/Upgrade sudo apt-get clean sudo apt-get update sudo apt-get upgrade Redhat / CentOS / Fedora yum clean all yum update yum list updates yum update To install soft sudo apt-get install lxde List all installed packages, enter: # rpm … Continue reading

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Linux Single User Mode Reset Root Password

To do this reboot the Server as soon as you get the boot screen press ‘e’ (stands for edit) from keyboard. After you press ‘e’ from keyboard you would see a lot of text which may be clipped as per … Continue reading

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Ubuntu Firewall Command Line Examples

How do I see the current status of my firewall? sudo ufw status verbose How do I open tcp port # 22? To allow incoming tcp packets on port 22, enter: sudo ufw allow 22/tcp Verify it: sudo ufw status … Continue reading

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Linux Find and Copy Command Examples

find files less 46 bytes and delete /usr/bin/find /share/team/ -maxdepth 5 -type f -size -46 -print | xargs rm -f Recursively remove all empty directories find . -type d -empty -delete /usr/bin/find /share/teamleads/ -type d -empty -delete /usr/bin/find /home/ -type … Continue reading

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Zimbra distribution list how to add, remove, get list

How to get list of distribution list in zimbra email server zmprov gadl How to get distribution list attributes zmprov gdl dlname@knowledgelinux.com How to add distribution list in zimbra email server zmprov cdl newdlist@marskarthik.com How to remove distribution list from … Continue reading

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Setting Up NTP (Network Time Protocol) Server in RHEL/CentOS 7

Step 1: Install ntp server package #yum install ntp -y Step 2: Get official NTP servers located near to your location. I am using Asia servers for this setup server 0.asia.pool.ntp.org server 1.asia.pool.ntp.org server 2.asia.pool.ntp.org server 3.asia.pool.ntp.org Step 3: Open … Continue reading

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Zimbra: Get mailbox size with status, created and last login date

Shell script to get mailbox size with status, created and last login date in Zimbra Server zmaccts | grep “@” | awk ‘{print $1}’ > /tmp/mboxes.list date > /tmp/mboxsize.txt #echo “\n” >> /tmp/mboxsize.txt for mb in `cat /tmp/mboxes.list`; do status=`zmaccts … Continue reading

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