{"id":3287,"date":"2025-05-03T04:28:33","date_gmt":"2025-05-03T04:28:33","guid":{"rendered":"https:\/\/w3buddy.com\/?p=3287"},"modified":"2026-01-15T13:10:25","modified_gmt":"2026-01-15T07:40:25","slug":"troubleshooting-inter-node-network-issues-in-oracle-rac","status":"publish","type":"post","link":"https:\/\/w3buddy.com\/blog\/troubleshooting-inter-node-network-issues-in-oracle-rac\/","title":{"rendered":"Troubleshooting Inter-Node Network Issues in Oracle RAC"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">When working with Oracle Real Application Clusters (RAC), reliable network connectivity between nodes is critical. If communication between nodes becomes unstable or fails, one of the first steps is to test connectivity at both the public and private network levels.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Let\u2019s walk through a practical approach to test node-to-node connectivity using the <code>ping<\/code> command with custom packet size and source IP options.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd0d Scenario Setup<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Assume we have a two-node Oracle RAC setup:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Node A<\/strong>: Hostname <strong>racnode1<\/strong><\/li>\n\n\n\n<li><strong>Node B<\/strong>: Hostname <strong>racnode2<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Each node has both public and private IP configurations:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Public IPs: <strong>192.168.100.1 <\/strong>(Node A) and <strong>192.168.100.2 <\/strong>(Node B)<\/li>\n\n\n\n<li>Private IPs: <strong>172.16.0.1 <\/strong>(Node A) and <strong>172.16.0.2 <\/strong>(Node B)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd27 Testing Public Network Connectivity<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">On Node A:<\/h4>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-bash\">[grid@racnode1 ~]$ ping -s 9000 -c 2 -I 192.168.100.1 192.168.100.2<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">On Node B:<\/h4>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-bash\">[grid@racnode2 ~]$ ping -s 9000 -c 2 -I 192.168.100.2 192.168.100.1<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd27 Testing Private Network Connectivity<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">On Node A:<\/h4>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-bash\">[grid@racnode1 ~]$ ping -s 9000 -c 2 -I 172.16.0.1 172.16.0.2<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">On Node B:<\/h4>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-bash\">[grid@racnode2 ~]$ ping -s 9000 -c 2 -I 172.16.0.2 172.16.0.1<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udee0\ufe0f Understanding the Ping Options<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>-s 9000<\/strong>: Specifies the packet size (in bytes). Larger packets can help detect MTU (Maximum Transmission Unit) issues.<\/li>\n\n\n\n<li><strong>-c 2<\/strong>: Sends 2 packets only \u2014 enough to test without overwhelming the network.<\/li>\n\n\n\n<li><strong>-I [source IP]<\/strong>: Forces the use of a specific source IP, crucial when multiple interfaces exist.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u2757 Observing the Results<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If you see:<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-bash\">2 packets transmitted, 0 packets received, 100% packet loss<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">This indicates a complete communication failure between the source and destination IPs.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83e\udde9 Common Causes of Connectivity Failures<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\ud83d\udd25 <strong>Firewall restrictions<\/strong>: Ensure that port filtering or packet blocking isn\u2019t applied between the nodes.<\/li>\n\n\n\n<li>\ud83d\udd12 <strong>Security appliances<\/strong>: IPS\/IDS systems might block unusual or large packets.<\/li>\n\n\n\n<li>\ud83d\udcf6 <strong>Physical or switch-level issues<\/strong>: Check cables and port configurations.<\/li>\n\n\n\n<li>\u2699\ufe0f <strong>Interface misconfiguration<\/strong>: Ensure IP bindings and routes are correct on both nodes.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u2705 Final Tip<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Always double-check whether any changes to network security policies (e.g., firewall rules, ACLs, or intrusion detection systems) have been implemented recently. These can silently disrupt RAC node communication without immediate visibility.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>When working with Oracle Real Application Clusters (RAC), reliable network connectivity between nodes is critical. If communication between nodes becomes unstable or fails, one of the first steps is to test connectivity at both the public and private network levels. Let\u2019s walk through a practical approach to test node-to-node connectivity using the ping command with [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"googlesitekit_rrm_CAowu461DA:productID":"","footnotes":""},"categories":[1225],"tags":[],"class_list":["post-3287","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/posts\/3287","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/comments?post=3287"}],"version-history":[{"count":1,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/posts\/3287\/revisions"}],"predecessor-version":[{"id":3289,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/posts\/3287\/revisions\/3289"}],"wp:attachment":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/media?parent=3287"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/categories?post=3287"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/tags?post=3287"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}