This file is indexed.

/usr/share/doc/ppp/README.STATIC-IP is in ppp 2.4.5-5ubuntu1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
Static IP addresses support with mgetty/autoPPP
-----------------------------------------------

Debian PPP package includes a variant of ppp-2.3.0-static.diff, a patch to
ppp-2.3.0 to support using static IP addresses with Mgetty and AutoPPP. It
does not affect normal dynamic assignments. There is no need to re-compile
the kernel.

You should update the pap-secrets file to contain the entries of those users
you want to have static IP addresses. Typical entry might look like:

#client     server     secret     IP addresses
 jdoe         *        realpswd   207.69.189.15 
   *          *         ""            *
 
Also, inform your static IP users to include their IP when
connecting. E.g. run `pppd 207.69.189.15:`
Or for Windows folks, check the "Specify an IP address" option and
type in the IP.

Note: The second line is what most folks will use to authenticate
users who will be dynamically assigned their addresses by 
/dev/ttyXX. This along with the login option allows users to be PAP
authenticated against the /etc/passwd or /etc/shadow. If you enter each and
every user into your pap-secrets file and do not have the last line,
(wildcards line) you MUST place a "*" at the end of each users line. 
Without it, the authentication will fail.  For example:

#client     server     secret     IP addresses
 jdoe         *        passwd     207.69.189.15 *

This "*" at the end allows the patches to work properly without changing
the normal process.  The IP address is normally assigned via the
/etc/ppp/options.ttyXX file. The patches do not interfere with this process
at all. The only thing different is when the user tells pppd he has his own
address, pppd will allow him to use it, if he and his address are
authenticated via the pap-secrets file. The only thing to remember, is tell
your static IP users to set the "correct" IP or they will be assigned the
normal dynamic address.  (And of course that's not what we want :>) If you
have any questions....

While I tested this as many ways as our systems would allow, no warranty 
is implied.  They work well for us.  

Author: Jeff Myers <jmyers@southcom.net>