{"id":289,"date":"2020-07-15T16:18:17","date_gmt":"2020-07-15T15:18:17","guid":{"rendered":"https:\/\/blog.thomarite.uk\/?p=289"},"modified":"2020-07-15T16:51:12","modified_gmt":"2020-07-15T15:51:12","slug":"traceroute","status":"publish","type":"post","link":"https:\/\/blog.thomarite.uk\/index.php\/2020\/07\/15\/traceroute\/","title":{"rendered":"Traceroute"},"content":{"rendered":"\n<p>A good refresh about <a href=\"https:\/\/www.youtube.com\/watch?v=WL0ZTcfSvB4&amp;t=576s\">traceroute<\/a>. It is a very common tool for network troubleshooting so it is important to use it wisely<\/p>\n\n\n\n<p>Important points<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>ICMP vs UDP<\/strong>: most implementations do UDP (it can be blocked&#8230;)<\/li><li><em>Every probe is an independent trial!<\/em><\/li><li>Try to identify the characteristics and location of each hop<\/li><li>If there is a congestion\/<strong>delay issue in one hop<\/strong>, it has to be carried out to the next hops, if not, it is just prioritizing of the ICMP generation by that router\/hop.<\/li><li>You dont see the <strong>reverse path<\/strong> &#8211; Ask the other end (if possible) to send the traceroute from its end.<\/li><li>Border routers between providers can be a hot spot for issues.<\/li><li>Asymmetric paths can bite you.  Try to set the <strong>source address<\/strong> in your tests (from the provider IP, from your own space, etc)<\/li><li>Spot <strong>ECMP<\/strong> (in the same hop, you see several different IPs).  Multiple unequal length paths can be painful.<\/li><li><strong>MPLS<\/strong>: most times is hidden (TTL is removed). It can be tricky to spot. But it can be funny when you see the hops (with private IPs \ud83d\ude42<\/li><\/ul>\n\n\n\n<p>And if you are more interested in the paths than latency, this can be a good too:<\/p>\n\n\n\n<p><a href=\"https:\/\/github.com\/rucarrol\/traceflow\">https:\/\/github.com\/rucarrol\/traceflow<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A good refresh about traceroute. It is a very common tool for network troubleshooting so it is important to use it wisely Important points ICMP vs UDP: most implementations do UDP (it can be blocked&#8230;) Every probe is an independent trial! Try to identify the characteristics and location of each hop If there is a &hellip; <a href=\"https:\/\/blog.thomarite.uk\/index.php\/2020\/07\/15\/traceroute\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Traceroute&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-289","post","type-post","status-publish","format-standard","hentry","category-networks"],"_links":{"self":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts\/289","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/comments?post=289"}],"version-history":[{"count":8,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts\/289\/revisions"}],"predecessor-version":[{"id":297,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts\/289\/revisions\/297"}],"wp:attachment":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/media?parent=289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/categories?post=289"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/tags?post=289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}