linux_wiki:configure_networking_and_hostname_resolution_statically_or_dynamically

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linux_wiki:configure_networking_and_hostname_resolution_statically_or_dynamically [2018/03/18 16:13]
billdozor [Hostname Configuration]
linux_wiki:configure_networking_and_hostname_resolution_statically_or_dynamically [2019/05/25 23:50]
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-====== Configure Networking And Hostname Resolution Statically Or Dynamically ====== 
- 
-**General Information** 
- 
-Networking has changed from RHEL 6 to 7. You can still edit network scripts in /etc/sysconfig/network-scripts/, but the "preferred" method is using front end tools that tie into the NetworkManager service. 
- 
----- 
- 
-===== Troubleshooting Tools ===== 
- 
-Show IP Address of Devices 
-<code bash> 
-ip addr show 
-</code> 
-  * ifconfig is deprecated in RHEL 7. 
- 
-\\ 
-Show all Established Connections 
-<code bash> 
-ss 
-</code> 
- 
-\\ 
-Show Established and Listening TCP Connections 
-<code bash> 
-ss -ant 
-</code> 
- 
-flags: 
-  * a => show both established and listening 
-  * t => show tcp connections 
-  * n => do not resolve service names (ports) 
- 
-\\ 
-Other tools to use: 
-  * ping -c 5 (send 5 pings) 
-  * traceroute 
-  * tracepath 
-  * netstat - netstat has been deprecated (use ss instead), but can still be installed as part of the net-tools package 
- 
----- 
- 
-===== Network Manager ===== 
- 
-NetworkManager is the default network service in RHEL 7.  
-  * Main Service = NetworkManager.service 
-  * Tools to interface with NetworkManager 
-    * nm-connection-editor (GUI) 
-    * nmtui (ncurses based) 
-    * nmcli (cli) 
-  * Fallback service = network.service 
-    * This uses the traditional network scripts in /etc/sysconfig/network-scripts/ as a fallback if NetworkManager is not in control of an interface. 
- 
-\\ 
-Open GUI for network connections (GUI Only) 
-<code bash> 
-nm-connection-editor 
-</code> 
- 
-\\ 
-Open text based wizard 
-<code bash> 
-nmtui 
-</code> 
- 
-\\ 
-==== CLI Tool: nmcli ==== 
- 
-nmcli makes configuration changes to files in: /etc/sysconfig/network-scripts/ 
- 
-These files can alternatively be modified manually. 
- 
-\\ 
-Network Device Status 
-<code bash> 
-nmcli dev status 
-</code> 
- 
-\\ 
-Show all connection configurations 
-<code bash> 
-nmcli con show 
-</code> 
-  * Configurations location: /etc/sysconfig/network-scripts/ 
- 
-\\ 
-Example: Create new connection (dhcp) 
-<code bash> 
-nmcli con add con-name "mycon" autoconnect yes type ethernet ifname eth1 
-</code> 
- 
-\\ 
-Example: Create new connection (static ip) 
-<code bash> 
-nmcli con add con-name "mycon-static" autoconnect yes type ethernet ifname eth1 ipv4.method manual ip4 10.0.0.5/24 gw4 10.0.0.254 
-</code> 
-  * The above produces the following config: 
-    * /etc/sysconfig/network-scripts/ifcfg-mycon-static<code bash>TYPE=Ethernet    # from: 'type ethernet' 
-BOOTPROTO=none    # from: 'ipv4.method manual' 
-IPADDR=10.0.0.5    # from: 'ip4 10.0.0.5/24' 
-PREFIX=24    # from: 'ipv 10.0.0.5/24' 
-GATEWAY=10.0.0.254    # from: 'gw4 10.0.0.254' 
-DEFROUTE=yes 
-IPV4_FAILURE_FATAL=no 
-IPV6INIT=yes 
-IPV6_AUTOCONF=yes 
-IPV6_DEFROUTE=yes 
-IPV6_PEERDNS=yes 
-IPV6_PEERROUTES=yes 
-IPV6_FAILURE_FATAL=no 
-NAME=mycon-static    # from: 'con-name "mycon-static"' 
-UUID=f7e0c9af-715d-43da-9576-e6ce218d0c28 
-DEVICE=eth1    # from: 'ifname eth1' 
-ONBOOT=yes    # from: 'autoconnect yes'</code> 
- 
-\\ 
-Show only active connections 
-<code bash> 
-nmcli con show --active 
-</code> 
- 
-\\ 
-Bring connections up/down 
-<code bash> 
-nmcli con down "mycon-static" 
-nmcli con up "mycon" 
-</code> 
- 
-\\ 
-Change an existing connection's IP and Gateway 
-<code bash> 
-nmcli con mod eth0 ipv4.addresses 192.168.1.50/24 
-nmcli con mod eth0 ipv4.gateway 192.168.1.254 
-nmcli con mod eth0 ipv4.method manual 
-nmcli con up eth0 
-</code> 
-  * Changes do not take place until "nmcli con up eth0" 
- 
----- 
- 
-===== Hostname Configuration ===== 
- 
-View current hostname 
-<code bash> 
-hostname 
-</code> 
- 
-\\ 
-Set **temporary**(transient) hostname 
-<code bash> 
-hostname myserver.domain.com 
-exec bash 
-</code> 
- 
-\\ 
-View detailed hostname information 
-<code bash> 
-hostnamectl 
-</code> 
-  * static hostname (stored in: /etc/hostname) - used to initialize kernel at boot (persistent) 
-  * transient hostname - assigned temporarily due to network configuration, may revert back to static if network connectivity is lost 
-  * pretty hostname (stored in: /etc/machine-info) - little restrictions on characters used 
- 
-\\ 
-Set **persistent**(static) hostname 
-<code bash> 
-hostnamectl set-hostname myserver.com 
-</code> 
- 
-\\ 
-Order of name resolution (hosts entry) 
-<code bash> 
-/etc/nsswitch.conf 
- 
-#....other entries above 
- 
-# hosts: search local files and then DNS 
-hosts:      files dns 
- 
-#....other entries below 
-</code> 
- 
-\\ 
-System wide dns name server entries (static or network manager generated) 
-<code bash> 
-/etc/resolv.conf 
- 
-# Generated by NetworkManager 
-search us-west-2.compute.internal 
-nameserver 172.31.0.2 
-</code> 
- 
-\\ 
-Local system hostname resolution and example entry 
-<code bash> 
-/etc/hosts 
- 
-# IP      Hostname                Aliases 
-10.1.1.2  myserver01.example.com  website.domain.com 
-</code> 
- 
-\\ 
-**Add DNS** (not replace) for eth0 with nmcli or with config file 
-  * Using nmcli<code bash> 
-nmcli con show 
-(observe NAME field) 
-nmcli con mod "System eth0" +ipv4.dns 8.8.8.8</code> 
-  * Edit files directly<code bash> 
-vim /etc/sysconfig/network-scripts/ifcfg-eth0 
- 
-DNS1=8.8.8.8</code> 
-  * Apply changes: restart NetworkManager or issue nmcli command 
-  * nmcli method<code bash>nmcli con up eth0 
-  * Service restart<code bash>systemctl restart NetworkManager</code> 
- 
----- 
  
  • linux_wiki/configure_networking_and_hostname_resolution_statically_or_dynamically.txt
  • Last modified: 2019/05/25 23:50
  • (external edit)