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Name

gsmaccess - SMSLink server access control list file

Description

gsmaccess is an ASCII file which contains entries (rules) defining potential client's access rights to the server (in simple terms of allow / deny). Each rule will qualify as an "allow" or a "deny" rule, specifying the network number or individual IP address to which the rule apply and a subnet mask expressed as a single decimal digit.

There is one entry per line, and each line has the format:

access:network/netmask

Lines beginning with '#' are treated as comments and ignored. Empty lines are allowed and ignored. Invalid entries are silently ignored.

The field descriptions are:

access
a single character, either 'n' (=deny) or 'y' (=allow). The presence of this character is required. It is not case-sensitive.
network
a network number or IP address expressed as a dotted quad.
netmask
a subnet mask expressed as a single decimal value (representing the number of bits set in the mask). A mask of 32 would mean that the preceeding dotted quad represented an individual IP address.

Security Policy

If the file /etc/gsmaccess exists and can be read, the policy is to enable access control (even if the file is empty or doesn't contain any valid rule), and to deny access by default. All rules contained in the file are parsed in their successive order, and the first to match the client's IP address applies. When no match can be found, access is denied by default. To revert the policy to a "default allow", use only negative rules and set "y:0.0.0.0/0" as the last one.

When the file is absent, the access control is disabled altogether.

Examples

y:0.0.0.0/0
grants access to anyone.

y:192.1.1.0/24
n:192.1.1.7/32
grants access to anyone on the 192.1.1.0 subnet with mask 255.255.255.0 but specifically denies access to the machine whose IP address is 192.1.1.7.

n:192.1.1.0/24
n:192.1.2.0/24
y:0.0.0.0/0
closes access to a few networks and opens it to anything else.

Files

/etc/gsmaccess

See Also

sms_serv(1) , sendsms(1) , gsmdevices(5)

Copyright

SMSLink is (c) Les Ateliers du Heron, 1998-2006 by Philippe Andersson <philipa STRUDEL scarlet PUNKT be>. It has been originally written for Scitex Europe, S.A.

Part of the code is (c) Riccardo Facchetti.

The code also includes contributions from Philipp Klaus <pklaus@access.ch>, Andrew Worsley <epaanwo@asac.ericsson.se>, and numerous others. All contributors are acknowledged in the CHANGELOG document, and in the comment headers of the source files they modified.

SMSLink has been released to the public under the GNU GPL.

Home page: <http://smslink.sourceforge.net/ >

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