How to run a script after ppp interface is comes up under Linux

Posted on in Categories , , , , last updated February 6, 2007

Q. I am using Fedora Core Linux. How do I run a script called /etc/rapp/logtime.sh immediately after my ppp interface is up?

A. Point-to-Point Protocol (PPP), is data link protocol commonly used for dial-up internet access. It is used to establish a direct connection between two nodes. It can connect computers using serial cable, phone line, trunk line, cellular telephone, specialized radio links, or fiber optic links. Most Internet service providers use PPP for customers’ dial-up access to the Internet.

Fedora Core – /etc/ppp/ip-up.local file

Under Fedora Core / RHEL /CentOS Linux you need to create or edit file – /etc/ppp/ip-up.local (Debian / Ubuntu Linux user see below for more information).

There is also a file called /etc/ppp/ip-up and it should not be modified — make local all changes to /etc/ppp/ip-up.local file only.

Step # 1: Open /etc/ppp/ip-up.local file
# vi /etc/ppp/ip-up.local

Step # 2: You can call your shell script – /etc/rapp/logtime.sh or any other program from this file by adding following line:
/etc/rapp/logtime.sh

Save and close the file.

Step # 3: Set executable permission
Next set the file executable for the owner:
# chmod 700 /etc/ppp/ip-up.local
Then set the file executable for script – /etc/rapp/logtime.sh
# chmod +x /etc/rapp/logtime.sh

From now on, the file /etc/ppp/ip-up.local will be executed immediately after the ppp0 interface has been brought up by your dialer.

Debian / Ubuntu Linux

Under Debian / Ubuntu Linux put your script in /etc/ppp/ip-up.d/ directory itself. /etc/ppp/ip-up script is run by the pppd after the link is established. It uses run-parts to run scripts in /etc/ppp/ip-up.d you should create script(s) there.
# cp /etc/rapp/logtime.sh /etc/ppp/ip-up.d/
# chmod +x /etc/ppp/ip-up.d/logtime.sh

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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  1. If running from /etc/ppp/ip-up.d (or ip-down.d), you can’t have a . in the script name (a restriction of the default settings for run-parts). You can test which scripts will be run with
    “run-parts –test /etc/ppp/ip-up.d”

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