Transmission subscriber identification ( .sm tsi ) access control list
The \*(Fx configuration parameter QualifyTSI specifies whether or not the identity of a calling facsimile machine should be checked against an access control list before receiving facsimile. If QualifyTSI is non-null, then only messages from facsimile machines identified in the file specified by the string (typically etc/tsi) will be accepted.
Patterns are specified one per line and must conform to the regular expressions syntax specified by POSIX 1003.2; see re_format(7). Comments may be included; they are introduced with the ``#'' character and extend to the end of the line. Any trailing white space on a line is ignored (for convenience when comments are used).
If a line begins with ``!'', then the regular expression identifies clients that should be rejected; otherwise regular expressions identify clients whose transmissions should be accepted. The order of patterns in a TSI file is important. When a facsimile is to be received, the fax server will compare the client's TSI against the patterns in the access control list in the order in which they appear in the file. The first pattern that matches the client TSI is used to decide whether to accept or reject the facsimile. If no patterns match the client TSI then the facsimile is rejected. Thus if you want to accept all but a restricted set of TSI the last line in the file should be ``^.*$''.
Note that regular expression patterns should be written to match a TSI exactly. That is, patterns should be of the form:
^<pattern>$
where the ``^'' and ``$'' characters are used to specify the start and end of the matching TSI. Additionally, regular expression patterns should handle white space that may appear in known locations. For example,
^([+]1){1}[ .-]*415[ .-]*555[ .-]*1212.*$
matches the following TSI strings:
+1.415.555.1212
415 555 1212
1-415-555-1212
Finally, note that regular expressions can be used to specify many TSI with one pattern.
It would be nice if TSI that were to be matched against were placed in some canonical form (e.g. remove white space and white space-like characters). This is, however, problematic, because some facsimile machines permit any printable ASCII string to be sent as a TSI.