The steps below should work with FreePPP and MacPPP 2.14 or later when using static addressing with Open Transport.
How to set up a static IP with Open Transport and Free PPP
The key point in setting up a static IP address configuration with Open Transport is to place some of the IP information in the Config PPP settings.
These instructions assume you already know how to use the Config PPP control panel to some degree, and that you only need this tip for static IP addressing.
1) Open the Config PPP control panel and click the Config... button.
2) Choose Manual ISP (some versions may have Config instead) in the PPP Server Name pop-up menu.
3) Click IPCP Options...
4) Enter your assigned IP address number in the Local IP Address field.
5) Enter your Gateway IP address number in the Remote IP Address field. Click OK and exit the Config PPP control panel.
6) Open the TCP/IP control panel. Be sure you have chosen MacPPP in the Connect via pop-up window, and you have chosen Manually in the Configure pop-up window.
7) Enter your assigned IP address number in the IP Address field.
8) Enter your DNS (domain name server) IP address in the Name server addr field.
9) In the "Implicit Search Path: Starting domain name:" field enter your domain, for example, your.domain.com and close the TCP/IP control panel.