Configuring ISC Bind and DNS Connection Specific Suffix

Question

I'm pretty new to setting up DNS and DHCP servers. I've configured an ISC Bind 9 DNS server on Windows 10 on a network to have a local domain with forward and reverse zones and have the router pointing to it for local DNS.

Is the "Connection-specific DNS Suffix" that you see in Windows 10 ipconfig set specifically by the DHCP server, or is that somehow be configured by the DNS server and I missed it?

Luckily I can set a domain name in my router's DHCP configuration and it comes up as the "Connection-specific DNS Suffix" but asking for situations on other networks where I may not have as capable of a router.

Answer 1

It is provided by the DHCP server as part of the lease, as option 15 "Domain Name".

For example, in ISC DHCP Server (dhcpd) configuration syntax:

option domain-name "lan.example.com";

When making DNS queries, the suffix is appended by the client itself and the resulting queries just have the complete name. The DNS server doesn't actually know whether you relied on the suffix, or whether you typed the full name manually.

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There also is a similar option 119, "Domain Search", which allows you to provide multiple suffixes – but Windows did not actually support it until very recently, so stick to option 15 instead.