What is opensiqserver?

opensiqserver
is a Server software that implements the SIQ protocol for scoring based on facts or reputation of an IP/domain pair. It can be used as a base for antispam server-side solutions working for example with sendmail and milter-siq or any other SIQ client.
At start-up, opensiqserver listens on a configurable UDP port; when it receives a SIQ request from a Client (eg. militer-siq) it interrogates the configured RBL to obtain the reliability of the IP/domain pair listed in the request. The results obtained by RBL are combined by opensiqserver to obtain the answer parameters as defined in SIQ Protocol. The configuration files, including the list of RBL used, are in XML format and are easily customizable, in order to obtain the desired behaviour.

milter-siq
This Sendmail mail filter from SnertSoft will tag, reject and/or discard email, according to a score returned by a SIQ Protocol server that grades IP/domain pairs based on the server's reputation criteria.

SIQ protocol
The Server Index Query (SIQ) protocol is intended to provide standard means by which a mail exchange (MX) server can query one or more external services for scoring based on facts or reputation of an IP/domain pair. The SIQ protocol specifies the communication protocol used to transmit the IP/domain query and to return the query response.

How does Opensiqserver work?

Opensiqserver, according to the SIQ protocol, receives UDP requests (generated by a client software) containing source IP and sender domain of an incoming email. For each request Opensiqserver interrogates the blacklists defined in its configuration file; each of them returns a score. These scores (combined and normalized) are returned to the client through the SIQ protocol.

In the BLS configuration the Milter-siq component is responsible to the management of the SIQ Server response. The Milter-siq is a filter that can be added to sendmail so that every email received is first processed by the filter and possibly passed to sendmail.
When an email arrives, Milter-siq generates the request and sends it to the Siqserver, waiting for response. Accordingly to the response received by the opensiqserver, Milter-siq decides whether or not to accept the email.
However, this configuration is not the only possible implementation: opensiqserver works whith any SIQ protocol compliant client.

The objective is to decrease the number of e-mails processed by sendmail and/or any other antispam tools associated with it.


How to Install and configure opensiqserver

Installation
./configure && make && make install

Start Options

-h, --help	This small usage guide
-V, --Version	Output version information
-c, --config	Configuration file. Default is siqserver.cfg

Configuration Options
SIQServer configuration - file siqserver.cfg (must be in the same directory of the siqserver executable file) <?xml version="1.0" encoding="UTF-8"?> <SIQServer_configuration> <port> Listen port. In case of invalid value or in case of missing parameter the port 6262 is used. </port> <cache_validity> Time of validity of the cached objects expressed in seconds. In case of invalid value or in case of missing parameters the value 0 is used. </cache_validity> <logfile> Log file. In case of invalid value or in case of missing parameter the file "siqserver.log" is used. </logfile> <enable_cache> Enables or disables the cache. Valid values are 0 (disabled cache) and 1 (enabled cache). In case of invalid value or in case of missing parameters the cache is disabled. </enable_cache> <max_client_threads> Maximum number of request threads created. The requests in excess remain in waiting until one of the threads ends. In case of invalid value or in case of missing parameter the value 100 is used. </max_client_threads> <authoritative_lookup> Determines if the DNS queries are done directly to the BLs or to the configured DNS servers. Possible values are 0 (system DNS servers are used) or 1 (DNS queries done directly to BLs) </authoritative_lookup> <log_level> Logs level. Possible values are 0 (logs all), 1 (logs only warnings and errors), 2 (logs only errors), 3 (logs nothing). In case of invalid values or in case of missing parameter the value 1 is used. </log_level> <blrules> Blacklists rules file. In case of invalid value or in case of missing parameter the file "blrules.xml" is used. </blrules> </SIQServer_configuration>
 blrules file format
It's a XML file compound by n bl. Sections. Each bl section has these composition Rules.
<!DOCTYPE bl [ <!ELEMENT bl (name,type,url,results) > <!ELEMENT name (#PCDATA)> <!ELEMENT type (#PCDATA)> <!ELEMENT url (#PCDATA)> <!ELEMENT results (result+)> <!ELEMENT result (value,code,description,score)> <!ELEMENT value (#PCDATA)> <!ELEMENT code (#PCDATA)> <!ELEMENT description (#PCDATA)> <!ELEMENT score (#PCDATA)> ]> name - nome della black list type - rbl, erbl, dnsbl url - url della black list results - elenco dei risultati possibili value - valore ritornato dalla blacklist code - codice associato al valore ritornato description - descrizione associata al valore ritornato score - punteggio SIQ associato al valore ritornato

 milter-siq and Sendmail configuration
To see how to install/configure milter-siq with sendmail: milter-siq installation


More information about opensiqserver
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