DHCP options#

General information#

The Dynamic Host Configuration Protocol (DHCP) is a standard for passing configuration information to hosts on a TCP/IP network.

In addition to the service parameters, a cloud DHCP server always communicates the following options:

  • Router (option 3) – the first subnet address used;

  • Address Time (option 51) – the lease duration for the address (1 hour);

  • Hostname (option 12) – in the following format: ip-<IP address separated by hyphens>;

  • Domain Name (option 15) – <vpc-id>.internal is used by default.

Additionally, you can specify values for the following options:

  • Domain Server (option 6) – the DNS server address;

  • NTP Servers (option 42) – the NTP server addresses;

  • Domain Name (option 15) – the DNS domain name;

  • NETBIOS Name Srv (option 44) – the NETBIOS server name;

  • NETBIOS Node Type (option 46) – the NETBIOS node type.

When you create a VPC in NGN Cloud, an empty DHCP parameter set is automatically created. You can create your own DHCP parameters for your VPC.

Create/delete DHCP parameters#

To create a set of custom DHCP parameters, click Create.

You may specify just those parameters that your DHCP parameter set requires. An empty DHCP parameter set is created by default. You may assign your own domain name to your instances and use up to four of your own DNS servers.

Here is the list of supported DHCP parameters:

  • Domain name

  • DNS servers – List of IP addresses of domain name servers or AmazonProvidedDNS. We recommend using only one of the two parameters.

  • NTP servers – the IP addresses of Network Time Protocol (NTP) servers. You can specify up to four IP addresses.

  • WINS servers – the IP addresses of WINS servers. You can specify up to four IP addresses.

  • NetBIOS node type – the NetBIOS node type (1, 2, 4, or 8):

    • 1 – Broadcast (no WINS)

    • 2 – Peer-to-peer (WINS)

    • 3 – Mixed mode (broadcast then WINS)

    • 8 – Hybrid (WINS then broadcast)

Once a DHCP parameter set is created, it cannot be changed. To have the VPC use a different DHCP parameter set, create a new set and assign it to your VPC.

To delete unnecessary DHCP parameter sets, click Delete. Make sure that VPCs are now assigned another parameter set instead of the one they used.

Assign/reset DHCP parameters#

To assign the created DHCP parameter set to a VPC, click Assign.

After you assign a new parameter set to a VPC, all existing instances and any new instances you start in the VPC will use the new parameters. The applied DHCP options will be given back/returned by the DHCP server at the next access to it.

To reset the created DHCP parameter set and assign the default parameters, click Reset.