{"id":39602,"date":"2016-09-30T16:35:42","date_gmt":"2016-09-30T11:05:42","guid":{"rendered":"http:\/\/www.tothenew.com\/blog\/?p=39602"},"modified":"2016-10-03T15:09:08","modified_gmt":"2016-10-03T09:39:08","slug":"basics-of-iptables","status":"publish","type":"post","link":"https:\/\/www.tothenew.com\/blog\/basics-of-iptables\/","title":{"rendered":"Basics of IPTables"},"content":{"rendered":"

Linux<\/strong> is the most-used open source\u00a0operating system.\u00a0Managing network traffic<\/a> is one of the toughest jobs to deal with. \u00a0For this, we must configure the firewall<\/strong> in such a way that it meets the system and users requirements without leaving the system vulnerable.\u00a0The default firewall in most of the Linux distributions is IPTables.<\/strong><\/p>\n

IPTables<\/strong> is used to manage packet filtering, DNAT(Destination Network Address Translation), SNAT(Source Network Address Translation) rules. IPTables<\/strong> comes with all Linux distributions.<\/p>\n

\"Firewall\"<\/p>\n

To update\/install it, just retrieve the IPTables package:<\/p>\n

[js]
\nsudo apt-get install iptables
\n[\/js]<\/p>\n

IPTables<\/strong> might contain multiple tables and tables might contain multiple chains and chains contain multiple rules where rules are defined for the incoming and outgoing packets.
\nTherefore structure is IPTables -> Tables -> Chains -> Rules<\/strong>.<\/p>\n

\"Screenshot<\/p>\n

IPTables has the following 5 built-in tables:
\n\"Screenshot<\/p>\n

Mostly we play around with FILTER, NAT and MANGLE tables. There are five built-in chains in which we can place our firewall policy rules:<\/p>\n