nsupdate-client

A simple client to update DNS record from a remote client to a DNS server using nsupdate protocol, like No-IP or DynDNS for your own domain names.

Tested on Linux and OSX.

Requirements

• A DNS Server configured to accept updates (see below)
• Firewall with port 53/UDP open on the server
• dnsutils package on your server & clients

Configure your DNS server

Generate a public/private key pair:

dnssec-keygen -a HMAC-MD5 -b 512 -n HOST www.domain.com.

Configure your DNS zone like this:

zone "domain.com" {
  type master;
  file "/etc/bind/domain.com.hosts";
  allow-update { key "www.domain.com."; };
};

key "www.domain.com" {
  algorithm hmac-md5;
  secret "the-value-of-the-generated-key-that-you-can-see-in-public-and-private-keys ==";
};

Restart your DNS Server

/etc/init.d/bind9 restart

Usage on your client

Clone the project

git clone [email protected]:tomav/nsupdate-client.git

Copy the generated public/private keys on your machine. They must not be separated.

And then choose the command that fit your needs:

With static IP
./nsupdate-client -k Kdomain.com+xxxxxx.private -r sub.domain.com -l 600 -t A -d 192.168.1.100

With internal dynamic IP (where ethX is your interface name, like eth0, en1, ppp2...)
./nsupdate-client -k Kdomain.com+xxxxxx.private -r sub.domain.com -l 600 -t A -d if_ethX

With external dynamic IP 
./nsupdate-client -k Kdomain.com+xxxxxx.private -r sub.domain.com -l 600 -t A -d external

With CNAME
./nsupdate-client -k Kdomain.com+xxxxxx.private -r sub.domain.com -l 600 -t CNAME domain.com