{"id":609,"date":"2011-09-21T20:53:24","date_gmt":"2011-09-21T18:53:24","guid":{"rendered":"http:\/\/www.shukko.com\/x3\/?p=609"},"modified":"2011-09-21T20:53:24","modified_gmt":"2011-09-21T18:53:24","slug":"view-the-routing-cache-and-hits","status":"publish","type":"post","link":"https:\/\/www.shukko.com\/x3\/2011\/09\/21\/view-the-routing-cache-and-hits\/","title":{"rendered":"View the routing cache and hits"},"content":{"rendered":"

original: http:\/\/pingbin.com\/2011\/07\/view-the-routing-cache-and-hits\/<\/p>\n

Most of us check the normal thinks like traceroute or arp on a web server, but actually checking recent routing table lookup\u2019s can be a great tool. Doing this you can see if your actually using the right interface or if the application is even requesting the traffic to be routed by your OS.<\/p>\n

When\u00a0debugging\u00a0a networking issue it can be\u00a0invaluable\u00a0to see your linux servers current routes to get an idea of what\u2019s going on, also you can view the number of hits these routes have recently gotten, just look in the use\u00a0column\u00a0of the output table.<\/p>\n

\n
\n
?<\/a><\/div>\n\n\n\n
\n
1<\/div>\n<\/td>\n
\n
\n
route -neeC<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

You should see something like the following output:<\/p>\n

\n
\n
?<\/a><\/div>\n\n\n\n
\n
1<\/div>\n
2<\/div>\n
3<\/div>\n
4<\/div>\n
5<\/div>\n
6<\/div>\n
7<\/div>\n
8<\/div>\n<\/td>\n
\n
\n
root@:\/<\/code># route -neeC<\/code><\/div>\n
Kernel IP routing cache<\/code><\/div>\n
Source\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Destination\u00a0\u00a0\u00a0\u00a0 Gateway\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Flags Metric Ref\u00a0\u00a0\u00a0 Use Iface\u00a0\u00a0\u00a0 MSS\u00a0\u00a0 Window irtt\u00a0 TOS HHRef HHUptod\u00a0\u00a0\u00a0\u00a0 SpecDst<\/code><\/div>\n
78.46.172.35\u00a0\u00a0\u00a0 208.43.68.59\u00a0\u00a0\u00a0 192.0.2.1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2 venet0\u00a0\u00a0 1500\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 800\u00a0\u00a0 0\u00a0\u00a0 -1\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 78.46.172.35<\/code><\/div>\n
67.228.213.178\u00a0 78.46.172.35\u00a0\u00a0\u00a0 78.46.172.35\u00a0\u00a0\u00a0 l\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 23 lo\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 -1\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 78.46.172.35<\/code><\/div>\n
78.46.172.35\u00a0\u00a0\u00a0 72.46.130.42\u00a0\u00a0\u00a0 192.0.2.1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 venet0\u00a0\u00a0 1500\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 875\u00a0\u00a0 0\u00a0\u00a0 -1\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 78.46.172.35<\/code><\/div>\n
82.103.128.63\u00a0\u00a0 78.46.172.35\u00a0\u00a0\u00a0 78.46.172.35\u00a0\u00a0\u00a0 l\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 23 lo\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0 -1\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 78.46.172.35<\/code><\/div>\n
78.46.172.35\u00a0\u00a0\u00a0 174.34.156.130\u00a0 192.0.2.1\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1 venet0\u00a0\u00a0 1500\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 735\u00a0\u00a0 0\u00a0\u00a0 -1\u00a0\u00a0\u00a0 0\u00a0\u00a0\u00a0\u00a0\u00a0 78.46.172.35<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

From the above we can see some very interesting stats such as the interface used, source and destination IP\u2019s, metric, number of \u2018uses\u2019 and even the interface MTU<\/p>\n","protected":false},"excerpt":{"rendered":"

original: http:\/\/pingbin.com\/2011\/07\/view-the-routing-cache-and-hits\/ Most of us check the normal thinks like traceroute or arp on a web server, but actually checking recent routing table lookup\u2019s can be a great tool. Doing this you can see if your actually using the right interface or if the application is even requesting the traffic to be routed by your […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-609","post","type-post","status-publish","format-standard","hentry","category-kategerisiz"],"_links":{"self":[{"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/posts\/609","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/comments?post=609"}],"version-history":[{"count":1,"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/posts\/609\/revisions"}],"predecessor-version":[{"id":610,"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/posts\/609\/revisions\/610"}],"wp:attachment":[{"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/media?parent=609"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/categories?post=609"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shukko.com\/x3\/wp-json\/wp\/v2\/tags?post=609"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}