{"id":2691,"date":"2019-08-28T10:01:41","date_gmt":"2019-08-28T10:01:41","guid":{"rendered":"https:\/\/www.testpreptraining.com\/tutorial\/?page_id=2691"},"modified":"2020-05-01T09:47:27","modified_gmt":"2020-05-01T09:47:27","slug":"security-groups-and-nacls","status":"publish","type":"page","link":"https:\/\/www.testpreptraining.ai\/tutorial\/aws-certified-advanced-networking-specialty\/security-groups-and-nacls\/","title":{"rendered":"Security Groups and NACLs"},"content":{"rendered":"\n<ul class=\"wp-block-list\"><li>It acts as a virtual firewall for instance to\ncontrol inbound and outbound traffic. <\/li><li>After launching instance in VPC, can assign up\nto 5 security groups to instance. <\/li><li>Security groups act at instance level, not\nsubnet level. <\/li><li>each instance in a subnet in VPC could be\nassigned to a different set of security groups. <\/li><li>If security group not specified at launch time,\nthe instance is automatically assigned to the default security group for the\nVPC.<\/li><li>Can add rules to control inbound traffic to\ninstances, <\/li><li>separate set of rules to control the outbound\ntraffic.<\/li><li>have limits on <ul><li>number\nof security groups, can be created per VPC, <\/li><\/ul><ul><li>number\nof rules, can be added to each security group<\/li><\/ul><ul><li>number\nof security groups, can be associated with a network interface. <\/li><\/ul><\/li><li>allow rules only can be specified <\/li><li>deny rules cannot be specified<\/li><li>inbound and outbound traffic can have their own\nseparate rules.<\/li><li>no inbound rules during security group creation<\/li><li>By default, a security group has outbound rule\nto allows all outbound traffic.<\/li><li>Security groups are stateful <\/li><li>if request is sent from instance, the response\ntraffic for that request is allowed to flow in regardless of inbound security\ngroup rules.<\/li><li>Irrespective of outbound rules, response to permitted\ninbound traffic, will be sent<\/li><li>Instances with a security group can&#8217;t talk to\neach other unless rules allow<\/li><li>All security group has a set of rules added to\nthem, by default<\/li><li>security group name and description should comply\nas<ul><li>Names\nand descriptions can be up to 255 characters in length.<\/li><\/ul><ul><li>Names\nand descriptions are limited to the following characters: a-z, A-Z, 0-9,\nspaces, and ._-:\/()#,@[]+=&amp;;{}!$*.<\/li><\/ul><ul><li>A\nsecurity group name cannot start with sg-.<\/li><\/ul><ul><li>The\nname of security group name should be unique in the VPC.<\/li><\/ul><\/li><\/ul>\n\n\n\n<p>Default rules for a\ndefault security group<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><td>Destination     <\/td><td>Protocol     <\/td><td>Port Range     <\/td><td>Comments    <\/td><\/tr><\/thead><tbody><tr><td>Inbound &#8211; The security group ID (sg-xxxxxxxx)   <\/td><td>All   <\/td><td>All   <\/td><td>Allow inbound traffic from instances assigned to the same   security group.   <\/td><\/tr><tr><td>Outbound &#8211;    0.0.0.0\/0   <\/td><td>All   <\/td><td>All   <\/td><td>Allow all outbound IPv4 traffic.   <\/td><\/tr><tr><td>Outbound &#8211;    &nbsp;   ::\/0    <\/td><td>All    <\/td><td>All    <\/td><td>Allow all outbound IPv6 traffic. This rule is added by default if you create a VPC with an IPv6 CIDR block or if you associate an   IPv6 CIDR block with existing VPC.   <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><strong>Security Group Rules<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>User can easily add or eliminate rules for a\nspecific security group <\/li><li>Security group rule can be applied either to\ningress\/inbound traffic to the security group&nbsp;\nor egress\/ outbound traffic to the security group. <\/li><li>Flexibility to grant access to <ul><li>specific\nCIDR range<\/li><\/ul><ul><li>another\nsecurity group in VPC <\/li><\/ul><ul><li>in\na peer VPC <\/li><\/ul><\/li><li>Following are applicable to security <\/li><li>Contents of security group rule in an AWS VPC<ul><li>Name\nof any protocol as specified by IANA, and as per standard protocol number. Like\nfor ICMP as protocol, can also enlist any or all of ICMP types and codes.<\/li><\/ul><ul><li>An\ndescription for security group rule.<ul><li>It\nis optional<\/li><\/ul><ul><li>Description\nhelps in identification, later. <\/li><\/ul><ul><li>Maximum\n255 characters in length. <\/li><\/ul><ul><li>Allowed\ncharacters are <ul><li>a-z<\/li><\/ul><ul><li>A-Z<\/li><\/ul><ul><li>&nbsp;0-9<\/li><\/ul><ul><li>Spaces<\/li><\/ul><ul><li>&nbsp;._-:\/()#,@[]+=;{}!$*.<\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><li>&nbsp;<ul><li>For\nrules which act on Inbound <ul><li>Specify\nsource of traffic and destination port or port range<\/li><\/ul><ul><li>source\ncan be <ul><li>another security group<\/li><\/ul><ul><li>an IPv4 or IPv6 CIDR block<\/li><\/ul><ul><li>single IPv4 or IPv6 address.<\/li><\/ul><\/li><\/ul><\/li><\/ul><ul><li>For\nrules which act on Inbound<ul><li>Specify\ndestination for traffic and destination port or port range<\/li><\/ul><ul><li>destination\ncan be <ul><li>another security group<\/li><\/ul><ul><li>an IPv4 or IPv6 CIDR block<\/li><\/ul><ul><li>single IPv4 or IPv6 address<\/li><\/ul><ul><li>prefix list ID (ID of service for a Region).<\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"373\" height=\"400\" src=\"https:\/\/www.testpreptraining.ai\/tutorial\/wp-content\/uploads\/2019\/09\/image-282-373x400.png\" alt=\"\" class=\"wp-image-4040\" srcset=\"https:\/\/www.testpreptraining.ai\/tutorial\/wp-content\/uploads\/2019\/09\/image-282-373x400.png 373w, https:\/\/www.testpreptraining.ai\/tutorial\/wp-content\/uploads\/2019\/09\/image-282.png 472w\" sizes=\"auto, (max-width: 373px) 100vw, 373px\" \/><\/figure><\/div>\n\n\n\n<p><strong>NACLs<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Default NACLs allow all Inbound \/ Outbound traffic.<\/li><li>Custom NACLs by default deny all Inbound \/\nOutbound traffic.<\/li><li>stateless firewall<\/li><li>creation of an ACL has a default deny inbound\nand outbound<\/li><li>All of the subnets present in a VPC, should have\na NACL<\/li><li>&nbsp;Numbered\nlist of rules that are evaluated in order starting at the lowest numbered rule\nfirst to determine what traffic is allowed in or out depending on what subnet\nis associated with the rule <\/li><li>The highest rule number is 32766 <\/li><li>Usually the rule number to start is, 100 and\nthen more rules are added accordingly<\/li><li>Different rules to deny or allow traffic can be\napplied on either incoming or outgoing traffic<\/li><li>The default NACL present in VPC allows all\ntraffic both in or out<\/li><li>Any custom NACL when added, has default setting\nof denying all the traffic, till specific rules are added<\/li><li>You must assign a NACL to each subnet, if a\nsubnet is not associated with a NACL, it will allow no traffic in or out <\/li><li>NACL rules do not maintain any state&nbsp; <\/li><li>A single NACL can be assigned only to a single\nsubnet <\/li><li>After association of a NACl with a subnet, all\nof the past NACLs are deleted <\/li><li>A single NACL can be assigned to many subnets\nwhereas one subnet can have only one NACL<\/li><li>Each subnet in VPC must be associated with a\nNACL. If you don&#8217;t explicitly associate a subnet with an ACL, the subnet automatically\ngets associated with the default ACL <\/li><li>You can block IP addresses using NACLs not\nSecurity Groups<\/li><li>NACLs contain numbered rules evaluated in the\norder staring from the lowest one.<\/li><li>NACLs are stateless. Response to allow inbound\ntraffic is subject to outbound rules.<\/li><li>Ideally, only ephemeral ports should be allowed in outbound traffic  <\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"611\" height=\"354\" src=\"https:\/\/www.testpreptraining.ai\/tutorial\/wp-content\/uploads\/2019\/09\/image-283.png\" alt=\"\" class=\"wp-image-4041\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>It acts as a virtual firewall for instance to control inbound and outbound traffic. After launching instance in VPC, can assign up to 5 security groups to instance. Security groups act at instance level, not subnet level. each instance in a subnet in VPC could be assigned to a different set of security groups. If&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2468,"menu_order":33,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[7,438,468],"class_list":["post-2691","page","type-page","status-publish","hentry","tag-aws","tag-big-data-specialty","tag-security-groups-and-nacls"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Security Groups and NACLs - Testprep Training Tutorials<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.testpreptraining.ai\/tutorial\/aws-certified-advanced-networking-specialty\/security-groups-and-nacls\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Security Groups and NACLs - Testprep Training Tutorials\" \/>\n<meta property=\"og:description\" content=\"It acts as a virtual firewall for instance to control inbound and outbound traffic. After launching instance in VPC, can assign up to 5 security groups to instance. Security groups act at instance level, not subnet level. each instance in a subnet in VPC could be assigned to a different set of security groups. 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