Acs commands are composed of a command descriptor and a parameter. The command descriptor is a upper or lowercase letter. The param is a positive number from 0 to 32767. The parameter can be omitted, if it is, it defaults to 0.
p - True if user has a priv of at least the paramater
a - True if user has a access level of at least the parameter.
g - True if user has an age of at least the parameter
s1 - True if uucp is currently loaded.
s2 - True if sucker is currently loaded.
s3 - True if terminal is currently loaded.
s4 - True if MacPPP's state is OPEN
The following are the unimplemented commands:
s0 - True if user is male (using sexist acs's is unpolitically correct tho)
e1 - True if user has at least TTY (always true)
e2 - True if user has at least VT100 (true if has VT100, ANSI or RIP emulation)
e3 - True if user has at least ANSI (true if has ANSI, or RIP emulation)
e4 - True if user has RIP emulation
P - True if user has a post call ratio of 1 to param
r - True if user has a particular restriction (a..z) poss values (r1..r26)
t - True if the current time is equal or past the specified time in
military time
D - True if user has maintained a upload to download ratio of 1 to param
d - True if user has downloaded at least the param of kilobytes
u - True if user has uploaded at least the param of kilobytes
Each command returns a true or false which is used to see if the user will be able to gain access to a feature, such as telnet, and newsgroups.
Acs's have an implied AND between every command so something like "p3a3" would gain access only if BOTH commands returned true. But there are other special operators that allow you to evaluate the acs expression differently.
& - Immediate AND
! - NOT command
| - OR command
The OR operator takes the commands and returns a true if either command returns a true, or a false if neighter do. The Immediate AND operator is just like the implied one, only it is evaluated first. The NOT operator takes the command after it and returns a true if the command returned a false, and a false if it returned true.
The order the operators are evaluated is very important. The order is &, !, | and then the implied AND. This makes possible the following "g18|a2&g16".
That would allow a user of access level of zero through one and at least 18 years old, or if he was access level 2 he would only have to be at least 16 years old. The order the acs is evaluated in is very important. Look at "g18|a2g16" It looks the same, but it evaluated differntly because the | operator is evaluated before the implied AND.
Look at the following tables, the commands have been replaced to 1 or 0 for all the possible values. The first column is the first example, and second column is the second example, see how they evaluate differently:
0|00 = 0 0|0&0 = 0
0|01 = 0 0|0&1 = 0
0|10 = 0 0|1&0 = 0
0|11 = 1 0|1&1 = 1
1|00 = 0 1|0&0 = 0
1|01 = 1 1|0&1 = 0
1|10 = 0 1|1&0 = 0
1|11 = 1 1|1&1 = 1
The NOT operator ! is used to make a command operate in the oposite way. For example r13 returns true if the user has the "m" restriction, !r13 would return true if the user DOESN'T have the "m" restriction. !a5 would return true if the user has a access level of 4 or lower.
Well that concludes my trying to teach people how to use acs's properly, if you still don't understand you don't need to know more than that "a1p2g16r13" will be true if the user has at least and access level of 1, a priv of 2, and age of 16, and restriction 13.
