In this short tutorial I will show how to check TCP/UDP open port or services in FreeBSD box. For checking open port or services which uses port in FreeBSD simply issue the following commands. check TCP connection sockstat -Ptcp check UDP connection sockstat -PudpCombine with grep to search port used by specific service or service which using specific port. use grep to get service or port ...
DRBD refers to block devices designed as a building block to form high availability cluster. This is done by mirroring a whole block device via an assigned network. DRBD can be understood as network based RAID-1. (DRBD) Sometimes we have a disk failure on hard drive which contains DRBD backing device. The following steps can be used to replace or recover the failed drive. detach drbd resource from broken backing storage ...
Split Brain in DRBD is a condition where each host think that resource in another host is outdated, thus synchronization won’t be occured. This condition often occurs because of network or power failure which is indicated by these variables: log: Split-Brain detected, dropping connection connection-state: StandAlone/WFConnection To manually recover the cluster from split brain condition, the following steps is required. on victim connection state must be StandAlone # drbdadm disconnect <resource> set victim as secondary ...
It is usual task to find someone computer by its MAC address when there is an issue related to his computer in the local network. The common case is IP conflict or network abuse. But, if the MAC Address shows that machine is one of many scattered VMware virtual machine out there, how do we find it? vSphere Client If you have an VMware ESX or ESXi server, vSphere Client is tool to manage your virtual machines from remote computer. But, vSphere Client cannot tell the MAC Address of virtual machines from version 10 or higher and to find virtual machine based on MAC Address we must open the virtual machine Setting one by one. It is still possible when there are few virtual, but it is exhausting when we have many virtual machine. ...
Zimbra is a well known collaboration suite which includes email, calendaring, file sharing, activity streams, social communities and more. The most popular product from Zimbra is Zimbra Collaboration Server. Zimbra Collaboration Server comes with two version: Network Edition and Open Source Edition (FOSS). This documentation shows a simple way to install Zimbra Collaboration Server Open Source Edition in CentOS 6.5. Getting Started Prepare the system # yum update Disable SELinux ...
Icinga is a well-known server or network monitoring that runs in many Unix/Linux distribution. Server/Network monitoring is an essential part of Network Operations Center because by monitoring network engineers can always get the feedback and status from network and production servers. This is a simple documentation of Icinga installation in Scientific Linux 6.4 server. Getting started Before we install icinga, it best to keep our system updated. # yum update Search icinga package using yum search in RPMForge repository. ...
Cacti is a network graphic monitoring tools which used the potential of RRDTool. RRDTool is a data logging and graphing system for time series data. Cacti can show us a real time performance of network or servers which make this software become one of the most popular open source monitoring software. Getting Started Always update your box before we install new software. # yum update Install dependencies for cacti. ...
Hello, I want to share a documentation how to setup a mail server using CentOS 6.5 using Postfix as SMTP server and Dovecot as IMAP/POP3 server. Postfix is a well known Message Transfer Agent that mostly used today and Dovecot is also one of the widely used Mail User Agent. Preparing The Machine In this documentation we use a CentOS 6.5 server and before we start, let’s update the system. # yum update A mail server needs to have a MX record in its DNS, so make sure we have that. It is also a good thing to set the PTR record pointing to our domain too. ...
CentOS community now works together with Redhat alongside Fedora. It’s good news. So, we can hope to get a better software and support for next release of our beloved CentOS. As one of Linux (CentOS) fan, I want to share my experience installing nginx (engine-x) in CentOS 6.5. My VPS was installed as minimal server and then I added new packages, such as “Development tools” group and new repos (EPEL, CentALT). ...
When we rent a VPS, we will get a public IP address so we can access our VPS from anywhere in this world. But, sometimes we want a better way to access our VPS using Domain Name. We will have to rent a domain name from a Domain Name Registrar and then set up our Name server so that our domain name refer to our IP address. There is usually an easier way by using our registrar control panel to set up NS records. But, if you still want to set up your own Name server, I hope this documentation will be useful for you. ...