Connecting to a network with a static IP
by Uday R. Sawant, William Leemans, Jonathan Hobson, Oliver Pelz
Linux: Powerful Server Administration
- Linux: Powerful Server Administration
- Table of Contents
- Linux: Powerful Server Administration
- Linux: Powerful Server Administration
- Credits
- Preface
- 1. Module 1
- 1. Managing Users and Groups
- 2. Networking
- Introduction
- Connecting to a network with a static IP
- Installing the DHCP server
- Installing the DNS server
- Hiding behind the proxy with squid
- Being on time with NTP
- Discussing load balancing with HAProxy
- Tuning the TCP stack
- Troubleshooting network connectivity
- Securing remote access with OpenVPN
- Securing a network with uncomplicated firewall
- Securing against brute force attacks
- Discussing Ubuntu security best practices
- 3. Working with Web Servers
- Introduction
- Installing and configuring the Apache web server
- Serving dynamic contents with PHP
- Hosting multiple websites with a virtual domain
- Securing web traffic with HTTPS
- Installing Nginx with PHP_FPM
- Setting Nginx as a reverse proxy
- Load balancing with Nginx
- Setting HTTPs on Nginx
- Benchmarking and performance tuning of Apache
- Securing the web server
- Troubleshooting the web server
- 4. Working with Mail Servers
- 5. Handling Databases
- Introduction
- Installing relational databases with MySQL
- Storing and retrieving data with MySQL
- Importing and exporting bulk data
- Adding users and assigning access rights
- Installing web access for MySQL
- Setting backups
- Optimizing MySQL performance – queries
- Optimizing MySQL performance – configuration
- Creating MySQL replicas for scaling and high availability
- Troubleshooting MySQL
- Installing MongoDB
- Storing and retrieving data with MongoDB
- 6. Network Storage
- 7. Cloud Computing
- 8. Working with Containers
- Introduction
- Installing LXD, the Linux container daemon
- Deploying your first container with LXD
- Managing LXD containers
- Managing LXD containers – advanced options
- Setting resource limits on LXD containers
- Networking with LXD
- Installing Docker
- Starting and managing Docker containers
- Creating images with a Dockerfile
- Understanding Docker volumes
- Deploying WordPress using a Docker network
- Monitoring Docker containers
- Securing Docker containers
- 9. Streaming with Ampache
- 10. Communication Server with XMPP
- 11. Git Hosting
- Introduction
- Installing Git
- Creating a local repository with Git CLI
- Storing file revisions with Git commit
- Synchronizing the repository with a remote server
- Receiving updates with Git pull
- Creating repository clones
- Installing GitLab, your own Git hosting
- Adding users to the GitLab server
- Creating a repository with GitLab
- Automating common tasks with Git hooks
- 12. Collaboration Tools
- 13. Performance Monitoring
- 14. Centralized Authentication Service
- 2. Module 2
- 1. Installing CentOS
- Introduction
- Downloading CentOS and confirming the checksum on Windows or OS X
- Creating USB installation media on Windows or OS X
- Performing an installation of CentOS using the graphical installer
- Running a netinstall over HTTP
- Installing CentOS 7 using a kickstart file
- Getting started and customising the boot loader
- Troubleshooting the system in rescue mode
- Updating the installation and enhancing the minimal install with additional administration and development tools
- 2. Configuring the System
- Introduction
- Navigating text files with less
- Introduction to Vim
- Speaking the right language
- Synchronizing the system clock with NTP and the chrony suite
- Setting your hostname and resolving the network
- Building a static network connection
- Becoming a superuser
- Customizing your system banners and messages
- Priming the kernel
- 3. Managing the System
- Introduction
- Knowing and managing your background services
- Troubleshooting background services
- Tracking system resources with journald
- Configuring journald to make it persistent
- Managing users and their groups
- Scheduling tasks with cron
- Synchronizing files and doing more with rsync
- Maintaining backups and taking snapshots
- Monitoring important server infrastructure
- Taking control with GIT and Subversion
- 4. Managing Packages with YUM
- 5. Administering the Filesystem
- 6. Providing Security
- 7. Building a Network
- 8. Working with FTP
- 9. Working with Domains
- 10. Working with Databases
- 11. Providing Mail Services
- 12. Providing Web Services
- 13. Operating System-Level Virtualization
- 14. Working with SELinux
- 15. Monitoring IT Infrastructure
- 1. Installing CentOS
- 3. Module 3
- 1. Working with KVM Guests
- 2. Deploying RHEL "En Masse"
- 3. Configuring Your Network
- 4. Configuring Your New System
- 5. Using SELinux
- 6. Orchestrating with Ansible
- 7. Puppet Configuration Management
- 8. Yum and Repositories
- 9. Securing RHEL 7
- 10. Monitoring and Performance Tuning
- Bibliography
- Index
When you install Ubuntu server, its network setting defaults to dynamic IP addressing, that is, the network management daemon in Ubuntu searches for a DHCP server on the connected network and configures the network with the IP address assigned by DHCP. Even when you start an instance in the cloud, the network is configured with dynamic addressing using the DHCP server setup by the cloud service provider. In this chapter, you will learn how to configure the network interface with static IP assignment.
You will need an Ubuntu server with access to the root account or an account with sudo privileges. If network configuration is a new thing for you, then it is recommended to try this on a local or virtual machine.
Follow these steps to connect to the network with a static IP:
- Get a list of available Ethernet interfaces using the following command:
$ ifconfig -a | grep eth
- Open
/etc/network/interfacesand find the following lines:auto eth0 iface eth0 inet dhcp
- Change the preceding lines to add an IP address, net mask, and default gateway (replace samples with the respective values):
auto eth0 iface eth0 inet static address 192.168.1.100 netmask 255.255.255.0 gateway 192.168.1.1 dns-nameservers 192.168.1.45 192.168.1.46
- Restart the network service for the changes to take effect:
$ sudo /etc/init.d/networking restart - Try to ping a remote host to test the network connection:
$ ping www.google.com
In this recipe, we have modified the network configuration from dynamic IP assignment to static assignment.
First, we got a list of all the available network interfaces with ifconfig -a. The -a option of ifconfig returns all the available network interfaces, even if they are disabled. With the help of the pipe (|) symbol, we have directed the output of ifconfig to the grep command. For now, we are interested with Ethernet ports only. The grep command will filter the received data and return only the lines that contain the eth character sequence:
ubuntu@ubuntu:~$ ifconfig -a | grep eth eth0 Link encap:Ethernet HWaddr 08:00:27:bb:a6:03
Here, eth0 means first Ethernet interface available on the server. After getting the name of the interface to configure, we will change the network settings for eth0 in interfaces file at /etc/network/interfaces. By default, eth0 is configured to query the DHCP server for an IP assignment. The eth0 line auto is used to automatically configure the eth0 interface at server startup. Without this line, you will need to enable the network interface after each reboot. You can enable the eth0 interface with the following command:
$ sudo ifup eth0
Similarly, to disable a network interface, use the following command:
$ sudo ifdown eth0
The second iface eth0 inet static line sets the network configuration to static assignment. After this line, we will add network settings, such as IP address, netmask, default gateway, and DNS servers.
After saving the changes, we need to restart the networking service for the changes to take effect. Alternatively, you can simply disable the network interface and enable it with ifdown and ifup commands.
The steps in this recipe are used to configure the network changes permanently. If you need to change your network parameters temporarily, you can use the ifconfig and route commands as follows:
- Change the IP address and netmask, as follows:
$ sudo ifconfig eth0 192.168.1.100 netmask 255.255.255.0 - Set the default gateway:
$ sudo route add default gw 192.168.1.1 eth0 - Edit
/etc/resolv.confto add temporary name servers (DNS):nameserver 192.168.1.45 nameserver 192.168.1.46
- To verify the changes, use the following command:
$ ifconfig eth0 $ route -n
- When you no longer need this configuration, you can easily reset it with the following command:
$ ip addr flush eth0 - Alternatively, you can reboot your server to reset the temporary configuration.
You may need to configure your Ubuntu server for IPv6 IP address. Version six IP addresses use a 128-bit address space and include hexadecimal characters. They are different from simple version four IP addresses that use a 32-bit addressing space. Ubuntu supports IPv6 addressing and can be easily configured with either DHCP or a static address. The following is an example of static configuration for IPv6:
iface eth0 inet6 static address 2001:db8::xxxx:yyyy gateway your_ipv6_gateway
You can find more details about network configuration in the Ubuntu server guide:
- https://help.ubuntu.com/lts/serverguide/network-configuration.html
- Checkout the Ubuntu wiki page on IP version 6 - https://wiki.ubuntu.com/IPv6
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