jun 122019
 

Below are a collection of example netplan configurations for common scenarios. If you see a scenario missing or have one to contribute, please file a bug against this documentation with the example using the links at the bottom of this page. Thank you!

Configuration

To configure netplan, save configuration files under /etc/netplan/ with a .yamlextension (e.g. /etc/netplan/config.yaml), then run sudo netplan apply. This command parses and applies the configuration to the system. Configuration written to disk under /etc/netplan/ will persist between reboots.

Using DHCP and static addressing

To let the interface named ‘enp3s0’ get an address via DHCP, create a YAML file with the following:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      dhcp4: true

To instead set a static IP address, use the addresses key, which takes a list of (IPv4 or IPv6), addresses along with the subnet prefix length (e.g. /24). Gateway and DNS information can be provided as well:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      addresses:
        - 10.10.10.2/24
      gateway4: 10.10.10.1
      nameservers:
          search: [mydomain, otherdomain]
          addresses: [10.10.10.1, 1.1.1.1]

Continue reading »

nov 072014
 
According to RFC2821 the lowest-numbered records are the most preferred MX for domain. So I’ve a target Postfix backup server to keep the messages in a queue waiting for the primary server to become available. This ensures that if my primary MX goes down I do not loss any emails. However, spammers are connecting to my backup MX to avoid anti spam filters that are running on the primary MX server. This also hides their real IP from my primary MX. How do I configure anti-spam for my backup RHEL / CentOS 5.3 based Postfix mx server?


This is well known issue. Make sure your backup MX runs the same config in terms of spam rejection as your primary server. Try the following to improve backup eMail server anti spam configuration.

If the backup MX acts as a store-and-forward mail server

Consider the following example:

nixcraft.com.	86400	IN	MX 	10 mx01.nixcraft.net.in.
nixcraft.com.	86400	IN 	MX 	20 mx02.nixcraft.net.in.

nixcraft.com email handled by two email servers. mx02.nixcraft.net.in is your backup server. Open main.cf and append the following restrictions on mx02.nixcraft.net.in. Continue reading »