{"id":119,"date":"2017-09-14T16:04:08","date_gmt":"2017-09-14T14:04:08","guid":{"rendered":"http:\/\/www.quisted.net\/?p=119"},"modified":"2017-09-14T16:04:08","modified_gmt":"2017-09-14T14:04:08","slug":"ospf-route-filtering","status":"publish","type":"post","link":"https:\/\/www.quisted.net\/index.php\/2017\/09\/14\/ospf-route-filtering\/","title":{"rendered":"OSPF Route Filtering and Summarization"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_80 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.quisted.net\/index.php\/2017\/09\/14\/ospf-route-filtering\/#OSPF_Route_filtering_between_areas\" >OSPF Route filtering between areas<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.quisted.net\/index.php\/2017\/09\/14\/ospf-route-filtering\/#OSPF_Route_filtering_into_the_Route_Table\" >OSPF Route filtering into the Route Table<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.quisted.net\/index.php\/2017\/09\/14\/ospf-route-filtering\/#OSPF_Route_Summerization\" >OSPF Route Summerization<\/a><\/li><\/ul><\/nav><\/div>\n<h3><span class=\"ez-toc-section\" id=\"OSPF_Route_filtering_between_areas\"><\/span>OSPF Route filtering between areas<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>Filtering prevents the creation of LSAs.<\/li>\n<li>LSDB&#8217;s have to be the same for all routers ifnot SPF logic will fail<\/li>\n<li>OSPF can filter the originiation of LSA between areas<\/li>\n<li>Type 3 LSAs are filtered <strong>prior to origination<\/strong> ABR\n<ul>\n<li style=\"list-style-type: none;\">\n<ul>\n<li>With multiple ABRs filtering should be done on both.<\/li>\n<li><em>ospf# <strong>area<\/strong> number <strong>prefix-list prefix<\/strong> name in|out<\/em>\n<ul>\n<li><strong>In:<\/strong> IOS filters routes comming in to that area<\/li>\n<li><strong>out:<\/strong> IOS filters routes comming out of that area<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre>ip prefix-list <span style=\"color: #ff9900;\">NAME<\/span> seq 5 deny 10.10.10.0\/24 le 32\nip prefix-list <span style=\"color: #ff9900;\">NAME<\/span> seq 10 permit 0.0.0.0\/0 le 32\n\nR1#(config-router)#area 1 filter-list prefix <span style=\"color: #ff9900;\">NAME<\/span> in\nR1#show ip ospf database summary self-originate<\/pre>\n<p><!--more--><\/li>\n<li>Type 5 LSAs are filtered at ASBR<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<ul>\n<li><strong>Filtering with Area-Range<\/strong>\n<ul>\n<li><em>ospf# <strong>area<\/strong> number range &lt;subnet&gt;&lt;mask&gt; not-advertise<br \/>\n<\/em><\/li>\n<li>Used for route summarization<\/li>\n<li>not-advertise turns it into a filter<\/li>\n<li>Doesn&#8217;t requite ACL or Prefix-Lists<\/li>\n<li>Only works with Type 1 and Type 2 LSAs<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre>R1#(config-router)#area 1 range 10.10.10.0 255.255.255.0 not-advertise\n<\/pre>\n<h3><span class=\"ez-toc-section\" id=\"OSPF_Route_filtering_into_the_Route_Table\"><\/span>OSPF Route filtering into the Route Table<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>Filter between OSPF database and Routing table.<\/li>\n<li>Router still have LSAs for the routes but after running SPF these routes are filtered using a distribute-list and don&#8217;t make it in the routing table.<\/li>\n<li>Can implemented on any OSPF router<\/li>\n<li><em>distribute-list prefix <span style=\"color: #ff9900;\">NAME<\/span> in &lt;interface&gt;<\/em><\/li>\n<li><em>distribute-list <span style=\"color: #3366ff;\">ACL<\/span> in &lt;interface&gt;<\/em><\/li>\n<li><\/li>\n<\/ul>\n<pre>access-list <span style=\"color: #3366ff;\">1<\/span> deny <span style=\"color: #339966;\">10.10.10.0 0.0.0.255<\/span>\naccess-list <span style=\"color: #3366ff;\">1<\/span> permit any\nR1#(config-router)#distribute-list <span style=\"color: #3366ff;\">1<\/span> in\n<\/pre>\n<ul>\n<li>extended acl to deny a<span style=\"color: #339966;\"> route<\/span> from a<span style=\"color: #ff9900;\"> specific neighbor<\/span><\/li>\n<\/ul>\n<pre>access-list <span style=\"color: #3366ff;\">101<\/span> deny ip host <span style=\"color: #ff9900;\">1.1.1.2<\/span> <span style=\"color: #339966;\">10.10.10.0 0.0.0.255<\/span>\naccess-list <span style=\"color: #3366ff;\">101<\/span> permit any any \nR1#(config-router)#distribute-list <span style=\"color: #3366ff;\">101<\/span> in\n<\/pre>\n<h3><span class=\"ez-toc-section\" id=\"OSPF_Route_Summerization\"><\/span>OSPF Route Summerization<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>Only on ABR and ASBR<\/li>\n<li>Creates new LSA<\/li>\n<li>ASBR creates Type 5 LSA<\/li>\n<\/ul>\n<pre>ABR:\nR1#(config-router)#area 1 range 1.1.0.0 255.255.252.0\n\nASBR:\nR1#(config-router)#summary-address 1.1.0.0 255.255.252.0 \n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>OSPF Route filtering between areas Filtering prevents the creation of LSAs. LSDB&#8217;s have to be the same for all routers ifnot SPF logic will fail OSPF can filter the originiation of LSA between areas Type 3 LSAs are filtered prior to origination ABR With multiple ABRs filtering should be done on both. ospf# area number [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[14,8],"tags":[],"class_list":["post-119","post","type-post","status-publish","format-standard","hentry","category-ospf","category-route"],"_links":{"self":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/119","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/comments?post=119"}],"version-history":[{"count":0,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/119\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/media?parent=119"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/categories?post=119"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/tags?post=119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}