Re: [Users] NEW FEATURE: IP blacklists

Hi everybody, OpenSER 1.2.0 has new feature - IP Blacklist support. This is a low level filtering engine for the outgoing requests; low level, because the filtering is done based on IP, protocol, port, etc. Its primary purposes will be to prevent sending requests to critical IPs (like GWs) due DNS or to avoid sending to destinations that are known to be unavailable (temporary or permanent). Because of flexibility concerns, the filtering rules can be groups inside multiple lists. A rule: - matches based on IP/mask, proto, port and text pattern criteria - can be reversed applied A list: - can be read-only - it does not change during execution - have timeout per elements - elements expires after a configured timeout. How to use: =========== currently there are 2 ways of using the blacklists: 1) statically defining list in the configuration file and selecting which ones should be used for each request. You can define blacklists as follow: # filter out requests going to ips of my gws dst_blacklist = gw:{( tcp , 192.168.2.100 , 5060 , "" ),( any , 192.168.2.101 , 0 , "" )} # block requests going to "evil" networks dst_blacklist = net_filter:{ ( any , 192.168.1.100/255.255.255.0 , 0 , "" )} # block message requests with nasty words dst_blacklist = msg_filter:{ ( any , 192.168.20.0/255.255.255.0 , 0 , "MESSAGE*ugly_word" )} # block requests not going to a specific subnet dst_blacklist = net_filter2:{ !( any , 192.168.30.0/255.255.255.0 , 0 , "" )} a rule is defined by: protocol : TCP, UDP, TLS or "any" for anything port : number or 0 for any ip/mask test patter - is a filename like matching (see "man 3 fnmatch") applied on the outgoing request buffer (first_line+hdrs+body) From routing script, you can use the use_blacklist("name") function to select what blacklist to be applied for the current request. More than one list can be selected. If the destination address matches on of the selected rules, the send will fail. 2) via DNS The DNS resolver, when configured with failover, can automatically store in a temporary blacklist the failed destinations. This will prevent (for a limited period of time) openser to send requests to destination known as failed. So, the blacklist can be used as a memory for the DNS resolver. To use it, you have to enabled it - the rest is done automatically. disable_dns_blacklist = no By default is enabled. The temporary blacklist created by DNS resolver is named "dns" and it is by default selected for usage (no need use the use_blacklist() function. The rules from this list have a life time of 4 minutes - you can change it at compile time, from blacklists.h . To give you an internal snapshot, a new MI function - "list_blacklists" - was added to print all existent blacklists and their rules. Any suggestions/reports are welcome! regards, bogdan _______________________________________________ Users mailing list Users(a)openser.org http://openser.org/cgi-bin/mailman/listinfo/users