OSI , Network Address Translation (NAT). , , , L3, IP- , . IP-, , , (), IP-.
, , Port Address Translation (PAT). IP . OSI. PAT :

, ( ) . , 192.168.0.0 255.255.255.0. , Cisco Adaptive Security Appliances (ASA) . 192.168.0.X IP- Cisco ASA 208.104.33.225. , TCP 80, WEB , . ASA IP- 192.168.0.44 (208.104.33.225). , , ( 1024 1188). , WEB 208.104.33.241.
Intrusion Detection System (IDS), , . DDoS , .

, WEB , , . (IDS) , . , , . , .
, Intrusion Prevention System (IPS) , , . IPS :

, IPS . IPS/IDS :
- ;
- ;
- ;
- .
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