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Find open ports on the Linux server using a script

Find open ports on the Linux server using a script Create a .sh file with below script and set execute permission for the scrip file. #vi portscan.sh #!/bin/bash #The port numbers PORT1=21 #ftp PORT2=22 #ssh PORT3=25 #smtp PORT4=53 #dns PORT5=80 #http PORT6=110 #POP3 PORT7=143 #IMAP PORT8=443 #https PORT9=1433 #MSSQL PORT10=3306 #MYSQL PORT11=3389 #Microsoft-RDP PORT12=5432 #PostgreSQL […]

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Routing protocol commands list

CCNA Routing Protocol Commands IP ROUTING #sh ip route // To view IP routing tables created on a Cisco router. Static Routing Routers are manually configured for networks that are not directly connected, to be able to route to all networks via the next-hop interface. Syntax: (config)#ip route 192.168.10.0 255.255.255.0 192.168.20.2 (config)#no ip route 192.168.30.0 […]

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General Switch commands

Switch Commands Initial configuration of Switch1 with ip 172.16.10.16 >en #config t (config)#enable password cisco (config)#enable secret cisco (config)#hostname India-switch1 (config)#ip address 172.16.10.16 255.255.255.0 (config)#ip default-gateway 172.16.10.1 (config)#int f0/1 (config-if)#description Finance (config-if)#int f0/26 (config-if)#description Trunk (config-if)#exit (config)# Initial Configuration of 2950 Switch with ip 172.16.10.17 255.255.255.0 >en #config t (config)#hostame India-switch2 (config)#enable password cisco (config)#enable […]

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General Router Commands

Router Modes: Router> User mode Router# Privilege mode Router(config)# Configuration mode Router(config-if)# Interface configuration mode Router(config-subif) Sub Interface configuration mode Router(config-line)# Line mode Router(config-router)# Router configuration mode Global configuration mode in detail: Router> Can see Router config, but cannot change any settings Router# Can see Router config and move to config make changes Router#conf t […]

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Network Installation on Linux using NFS

The following package must be installed tftp , tftp server dhcp nfs Configure Dhcp Install dhcp,copy /usr/share/doc/dhcp-xxxx/dhcpd.conf.sample to /etc/dhcp/dhcpd.conf cp -r /usr/share/doc/dhcp-xxxx/dhcpd.conf.sample /etc/dhcp/dhcpd.conf vi dhcpd.conf option domain-name “your domain name”; option domain-name-servers YOUR-SERVER ; default-lease-time 600; max-lease-time 7200; allow bootp; allow booting; ignore client-updates; ddns-update-style none; not authoritative; log-facility local7; subnet YOUR-NETWORK netmask 255.255.255.0 { […]

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Open VPN Server Configuration on Linux

1. Install the OpenVPN RPM Before installing OpenVPN, make sure that all necessary dependencies are installed. Dependencies Required openssl lzo pkcs11-helper Once dependencies are ready, download the appropriate OpenVPN RPM package for your system: # wget https://path/to/openvpn-<version>.rpm # rpm -ivh openvpn-<version>.rpm After the installation completes, two directories will be created automatically: /etc/openvpn /usr/share/doc/openvpn-<version> 2. Copy […]

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Networking Concepts, in RHEL 7 or CENTOS7.

Networking Concepts in RHEL 7 or CentOS 7 When upgrading servers, you should focus on understanding how network configuration has evolved. In older versions of RHEL or CentOS, IP management was typically done by manually editing the network configuration files located under:/etc/sysconfig/network-scripts/ In contrast, the newer versions eliminate the need for direct file editing. Instead, […]

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