Pekka Helenius f5a10bcb18 | 6 years ago | |
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images | 6 years ago | |
LICENSE | 6 years ago | |
README.md | 6 years ago | |
wanchecker.sh | 6 years ago | |
wanchecker@.service | 6 years ago | |
wanchecker@.timer | 6 years ago |
WAN IPv4 checker & email notifier for server environments behind dynamic DHCP.
In many home networks, WAN (Wide Area Network) IP addresses are dynamically allocated by a local ISP. Usually this is acceptable in common household/home use, but not in server use where static DHCP lease/static IP address is very much a mandatory requirement.
However, static IPs are usually offered only to corporate environments, and not everyone wants to pay extra for such in order to establish a simple server environment in home.
This repository contains a systemd service file & a simple bash script to refresh current WAN IPv4 of a Linux server, and notify server admins for any changes in the server WAN IPv4 (Internet) address. This helps in several issues:
Server admins are always aware of the current server IPv4 address, whether the address is dynamic or not.
Server admins are able to remotely connect to the server environment although the server IP has been changed. This is possible because admins are notified about any WAN IPv4 address changes via email by the server itself, automatically.
A server computer of any kind
Linux OS
systemd - service file
SSMTP - (SMTP) email client (package: ssmtp
(Arch Linux), ssmtp
(Ubuntu))
dig (package: bind-tools
(Arch Linux), dnsutils
(Ubuntu))
bash
awk
systemd user service file: wanchecker@.service
systemd user timer file: wanchecker@.timer
bash script: wanchecker.sh
1) Insert wanchecker@.service
and wanchecker@.timer
into /usr/lib/systemd/user/
folder
20min
2) Insert wanchecker.sh
into your /home/myuser/
folder (where myuser
is your real username on your Linux system)
3) Configure your email address and message form in wanchecker.sh
file. In addition, configure WAN IPv4 log file location (default is $HOME
)
3) Install ssmtp
, and configure files /etc/ssmtp/revaliases
and /etc/ssmtp/ssmtp.conf
as described on SSMTP Arch Wiki site.
4) Run
systemctl --user enable wanchecker@myusername.timer && \
systemctl --user start wanchecker@myusername.timer
NOTE: If you change the shell script contents, make sure to run systemctl --user restart wanchecker@myusername.timer
afterwards.
Obviously, myusername
above refers to your true username on your Linux system.
When server computer discovers a change in its WAN IPv4, it automatically sends an email notification to system administrator(s):
Additionally, server computer keeps a log file which include WAN IPv4 changes and corresponding timestamps:
systemctl --user --all list-timers
= list all user-specific timers on Linux system, including wanchecker
systemctl --user is-active wanchecker@myusername.timer
= tells whether wanchecker is running or not
systemctl --user status wanchecker@myusername.timer
= more compherensive output about the status of wanchecker
etc.
This repository uses GPLv3 license. See LICENSE file for details.