namecheap-ddns-update

Update the IP address of your namecheap.com Dynamic DNS A records.

Overview

Use this to update the IP address of A records for one or more domains that are hosted by namecheap.com. If you created one or more A records using namecheap.com Dynamic DNS, then this will update the IP address to:

• The IP address you pass in as an argument using -i
• Or, if the -i is omitted or left blank, the IP address seen by namecheap.com's servers when you run this script. If you run this from within your network, then the externally visible IP address is used by namecheap.com to update the A record value. If you have a server with a public IP address, then this utility can be run from that server and -i can be omitted.

Running it

Check the help (-h) for details. The one argument that can only be set as an environment variable is NC_DDNS_PASS. The Dynamic DNS Password from namecheap.com's dashboard -> Advanced DNS page for the domain with the A records you want to update.

The remaining arguments can be set in one of the following ways:

1. Pass them in on the command line
2. Set them as environment variables e.g. export DOMAIN=domain.tld, or DOMAIN=domain.tld ./namecheap-ddns-update ....
3. Create an environment file .env in the same directory as the script. This file is sourced if it is found and is readable e.g. source ./.env (the .env.sample provides an example)
4. Create an environment file called .namecheap-ddns-update, in the directory of the user running this script. This file is sourced if it is found and is readable e.g. source ~/.namecheap-ddns-update

Basic usages is as follows:

Usage: namecheap-ddns-update [-h] [-e] [-d DOMAIN] [-s SUBDOMAINS] [-m MULTI_DOMAINS] [-i IP] [-t INTERVAL]

Update the IP address of one or more domains subdomains that you own at
namecheap.com. This can only update an existing A record, it cannot create
a new A record. Use namecheap's advanced DNS settings for your domain to
create A records.

For details on how this works see:
https://www.namecheap.com/support/knowledgebase/article.aspx/29/11/how-do-i-use-a-browser-to-dynamically-update-the-hosts-ip

The args d, s, m, i and t have corresponding ENV options. The Dynamic DNS
Password has to be set for each domain with the NC_DDNS_PASS environment
variable. If there is one domain being updated, then the format of the
NC_DNS_PASS value is the domain password. If you want to update multiple
domains, then the value is a comma separated list of domain/password pairs.
Example: NC_DNS_PASS=example.com=1a2s3d4f5g,example2.com=5g6h7j8k9l

You could also create an environment file in the same directory as the script,
called .env, or in directory of the user running this script, called
.namecheap-ddns-update. The .env file is sourced first if found, if it does
not exist, then .namecheap-ddns-update sourced if found.

    -h                display this help and exit
    -e                exit if any call to update a subdomains IP address fails
    -d DOMAIN         the domain that has one or more SUBDOMAINS (A records)
                      to update. DOMAIN/SUBDOMAINS can be used at the same
                      time as MULTI_DOMAINS to update multiple domains
    -s SUBDOMAINS     comma separated list of subdomains (A records) of DOMAIN
                      to update. DOMAIN/SUBDOMAINS can be used at the same
                      time as MULTI_DOMAINS to update multiple domains
    -m MULTI_DOMAINS  other domains to combine with subdomains (A records). It
                      can be specified multiple times on the command line,
                      at the same time specified as the environment variable
                      MULTI_DOMAINS. The format for the command line argument
                      is: -m example.com=abc,xyz -m example2.com=def,ghi. The
                      format for the environment variable is:
                      MULTI_DOMAINS=example.com=abc,xyz:example2.com=def,ghi
                      Each domain/subdomains pair is separated by a colon (:)
    -i IP             IP address to set the subdomain(s) to. If blank namecheap
                      will use the callers public IP address.
    -t INTERVAL       set up a interval at which to run this. Uses bash sleep
                      format e.g. NUMBER[SUFFIX] where SUFFIX can be, s for
                      seconds (default), m for minutes, h for hours, d for days

With a known public IP

This example would update the IP address to 127.0.0.1, for the two A records abc and xyz under the domain example.com e.g. abc.mydomain.com and xyz.example.com

./namecheap-ddns-update -d example.com -s "abc,xyz" -i 127.0.0.1

I don't know my public IP

This example runs every hour (1h) to update the IP address to the callers public IP address, for the two A records abc and xyz under the domain example.com e.g. abc.mydomain.com and xyz.example.com. This is useful when you sit behind an IP address that can change e.g. home internet service provider who dynamically assigns you a public IP address

./namecheap-ddns-update -d example.com -s "abc,xyz" -t 1h

I have multiple domains

This example updates multiple domains using the -m script argument.

./namecheap-ddns-update -d example.com -s "abc,xyz" -m example2.com=aaa,bbb -m example3.com=ccc,ddd

or using the MULTI_DOMAINS environment variable

MULTI_DOMAINS=example4.com=eee,fff:example5.com=ggg,hhh ./namecheap-ddns-update -d example.com -s "abc,xyz" -m example2.com=aaa,bbb -m example3.com=ccc,ddd

Docker

This docker container should be available from joshuamorris3/namecheap-ddns-update

docker run -e "NC_DDNS_PASS=123456" -e "DOMAIN=example.com" -e "SUBDOMAINS=abc,xyz" -e "INTERVAL=10s" -d --name nc-ddns joshuamorris3/namecheap-ddns-update

Docker compose instructions

Docker compose is a convienient way to start docker containers. The docker-compose.yml provides an example, it uses a file called .env (see .env.sample for an example) to configure the namecheap-ddns-update process.

To start the process using docker compose, simply run:

docker-compose up -d

Local docker instructions

You can also run this from within a Docker container.

Build your namecheap-ddns-update docker image

docker build -t namecheap-ddns-update -f Dockerfile .

Run the image you just built, passing in the environment variables to configure the script

docker run -e "NC_DDNS_PASS=123456" -e "DOMAIN=example.com" -e "SUBDOMAINS=abc,xyz" -e "INTERVAL=10s" -d --name nc-ddns namecheap-ddns-update