{"id":120,"date":"2013-11-07T18:30:33","date_gmt":"2013-11-07T09:30:33","guid":{"rendered":"http:\/\/tech.akat.info\/?p=120"},"modified":"2014-09-16T01:14:04","modified_gmt":"2014-09-15T16:14:04","slug":"mtu%e3%82%b5%e3%82%a4%e3%82%ba%e3%81%ae%e7%a2%ba%e8%aa%8d%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/tech.akat.info\/?p=120","title":{"rendered":"MTU\u30b5\u30a4\u30ba\u306e\u78ba\u8a8d\u65b9\u6cd5"},"content":{"rendered":"<h2>MTU(Maximum Transmission Unit)<\/h2>\n<p>\u901a\u4fe1\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u306b\u304a\u3044\u3066\u30011\u56de\u306e\u8ee2\u9001\u3067\u9001\u4fe1\u3067\u304d\u308b\u30c7\u30fc\u30bf\u306e\u6700\u5927\u5024\u3092\u793a\u3059\u5024\u306e\u3053\u3068\u3002<br \/>\n\u9001\u4fe1\u3059\u308b\u5074\u304c\u63a5\u7d9a\u3054\u3068\u306b\u5024\u3092\u8a2d\u5b9a\u3067\u304d\u308b\u3002<br \/>\n\u9001\u4fe1\u5074\u30db\u30b9\u30c8\u304c\u53d7\u4fe1\u5074\u30db\u30b9\u30c8\u3088\u308a\u5927\u304d\u3044MTU\u3092\u6301\u3063\u3066\u3044\u305f\u5834\u5408\u306f\u3001\u9001\u4fe1\u5074\u304c\u53d7\u4fe1\u5074\u306eMTU\u306b\u5f93\u3063\u3066\u30c7\u30fc\u30bf\u3092\u518d\u5206\u5272\u3057\u3066\u9001\u4fe1\u3059\u308b\u3002<\/p>\n<p>\u5358\u4f4d\u306f\u30d0\u30a4\u30c8\u3067\u3001Ethernet\u3067\u306f1500\u7a0b\u5ea6\u3001\u96fb\u8a71\u56de\u7dda\u306b\u3088\u308b\u30c0\u30a4\u30e4\u30eb\u30a2\u30c3\u30d7\u63a5\u7d9a\u3067\u306f576\u7a0b\u5ea6\u304c\u6700\u9069\u3068\u3055\u308c\u308b\u3002<br \/>\nhttp:\/\/e-words.jp\/w\/MTU.html<\/p>\n<h2>\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304b\u3089\u8a08\u6e2c\u3059\u308b<\/h2>\n<p>ping\u306e\u30aa\u30d7\u30b7\u30e7\u30f3<br \/>\n-l:\u9001\u4fe1\u3059\u308b\u30a8\u30b3\u30fc\u8981\u6c42\u30e1\u30c3\u30bb\u30fc\u30b8\u306e\u30c7\u30fc\u30bf\u30fb\u30d5\u30a3\u30fc\u30eb\u30c9\u306e\u9577\u3055\u3092\u6307\u5b9a<br \/>\n-f:IP\u30d8\u30c3\u30c0\u30fc\u5185\u306eDon&#8217;t Fragment\u30d5\u30e9\u30b0\u30921\u306b\u8a2d\u5b9a\u3057\u3066\u30a8\u30b3\u30fc\u8981\u6c42\u30e1\u30c3\u30bb\u30fc\u30b8\u3092\u9001\u4fe1\u3059\u308b<br \/>\n<a href=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_175850.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_175850-300x164.png\" alt=\"2013-11-07_175850\" width=\"300\" height=\"164\" class=\"alignnone size-medium wp-image-121\" srcset=\"https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_175850-300x164.png 300w, https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_175850-624x341.png 624w, https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_175850.png 665w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>\u30c7\u30fc\u30bf\u30d5\u30a3\u30fc\u30eb\u30c9\u304c1410\u30d0\u30a4\u30c8\u4ee5\u4e0a\u3067\u3042\u308c\u3070\u30d5\u30e9\u30b0\u30e1\u30f3\u30c8\u3092\u8d77\u3053\u3059\u3053\u3068\u304c\u308f\u304b\u308b<br \/>\n\u9001\u4fe1\u3055\u308c\u308b\u30d1\u30b1\u30c3\u30c8\u5168\u4f53\u306b\u3064\u3044\u3066<br \/>\n<a href=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181602.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181602-300x29.png\" alt=\"2013-11-07_181602\" width=\"300\" height=\"29\" class=\"alignnone size-medium wp-image-123\" srcset=\"https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181602-300x29.png 300w, https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181602-624x60.png 624w, https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181602.png 690w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\n\u30d7\u30ea\u30a2\u30f3\u30d6\u30eb\uff1a8\u30d0\u30a4\u30c8<br \/>\nMAC\u30a2\u30c9\u30ec\u30b9\uff1a6\u30d0\u30a4\u30c8<br \/>\ntype\uff1a2\u30d0\u30a4\u30c8<br \/>\nIP\u30d8\u30c3\u30c0\uff1a\u6700\u5c0f20\u30d0\u30a4\u30c8<br \/>\n<a href=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_182713.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_182713-300x182.png\" alt=\"2013-11-07_182713\" width=\"300\" height=\"182\" class=\"alignnone size-medium wp-image-125\" srcset=\"https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_182713-300x182.png 300w, https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_182713.png 475w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\nICMP\u30e1\u30c3\u30bb\u30fc\u30b8\uff1a\u30c7\u30fc\u30bf\u30d5\u30a3\u30fc\u30eb\u30c9\u3092\u9664\u304f\u3068\u30018\u30d0\u30a4\u30c8<br \/>\n<a href=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181631.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181631-300x90.png\" alt=\"2013-11-07_181631\" width=\"300\" height=\"90\" class=\"alignnone size-medium wp-image-124\" srcset=\"https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181631-300x90.png 300w, https:\/\/tech.akat.info\/wp-content\/uploads\/2013\/11\/2013-11-07_181631.png 482w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><br \/>\nFCS\uff1a4\u30d0\u30a4\u30c8<\/p>\n<p>MTU=8+6*2+2+20+8+1410+4=1464<br \/>\n\u3068\u3044\u3046\u3053\u3068\u306b\u3057\u3066\u304a\u304f\u3002\u3002<\/p>\n<h2>\u30b5\u30fc\u30d0\u304b\u3089\u8a08\u6e2c\u3059\u308b<\/h2>\n<p>\u3010\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u5074\u3011<br \/>\nping -f -l 1410 -n 1 tech.akat.info<\/p>\n<p>\u3010\u30b5\u30fc\u30d0\u5074\u3011<br \/>\nroot@akat:\/home\/shimizu# tcpdump -nevvv icmp<br \/>\ntcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes<br \/>\n19:12:35.977056 74:8e:f8:61:74:41 > (\u30b5\u30fc\u30d0MAC\u30a2\u30c9\u30ec\u30b9), ethertype IPv4 (0x0800), length 1452: (tos 0x0, ttl 115, id 15200, offset 0, flags [DF], proto ICMP (1), length 1438)<br \/>\n    (\u30af\u30e9\u30a4\u30a2\u30f3\u30c8IP\u30a2\u30c9\u30ec\u30b9) > (\u30b5\u30fc\u30d0IP\u30a2\u30c9\u30ec\u30b9): ICMP echo request, id 1, seq 34, length 1418<br \/>\n19:12:35.977116 (\u30b5\u30fc\u30d0MAC\u30a2\u30c9\u30ec\u30b9) > 00:00:5e:00:01:6f, ethertype IPv4 (0x0800), length 1452: (tos 0x0, ttl 64, id 32731, offset 0, flags [none], proto ICMP (1), length 1438)<br \/>\n    (\u30b5\u30fc\u30d0IP\u30a2\u30c9\u30ec\u30b9) > (\u30af\u30e9\u30a4\u30a2\u30f3\u30c8IP\u30a2\u30c9\u30ec\u30b9): ICMP echo reply, id 1, seq 34, length 1418<\/p>\n<p>\u2026length 1452 \u306a\u306e\u306f\u3001\u30d7\u30ea\u30a2\u30f3\u30d6\u30eb\u3068FCS\u3092\u8a08\u7b97\u3057\u3066\u3044\u306a\u3044\u304b\u3089\uff1f\u4e0d\u660e\u2026<\/p>\n<h2>\u53c2\u8003<\/h2>\n<p>http:\/\/www.atmarkit.co.jp\/fwin2k\/win2ktips\/652pingmtu\/pingmtu.html<\/p>\n","protected":false},"excerpt":{"rendered":"<p>MTU(Maximum Transmission Unit) \u901a\u4fe1\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u306b\u304a\u3044\u3066\u30011\u56de\u306e\u8ee2\u9001\u3067\u9001\u4fe1\u3067\u304d\u308b\u30c7\u30fc\u30bf\u306e\u6700\u5927\u5024\u3092\u793a\u3059\u5024\u306e\u3053\u3068\u3002 \u9001\u4fe1\u3059\u308b\u5074\u304c\u63a5\u7d9a\u3054\u3068\u306b\u5024\u3092\u8a2d\u5b9a\u3067\u304d\u308b\u3002 \u9001\u4fe1\u5074\u30db\u30b9\u30c8\u304c\u53d7\u4fe1\u5074\u30db\u30b9\u30c8\u3088\u308a\u5927\u304d\u3044M [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[11],"tags":[],"_links":{"self":[{"href":"https:\/\/tech.akat.info\/index.php?rest_route=\/wp\/v2\/posts\/120"}],"collection":[{"href":"https:\/\/tech.akat.info\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tech.akat.info\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tech.akat.info\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tech.akat.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=120"}],"version-history":[{"count":4,"href":"https:\/\/tech.akat.info\/index.php?rest_route=\/wp\/v2\/posts\/120\/revisions"}],"predecessor-version":[{"id":128,"href":"https:\/\/tech.akat.info\/index.php?rest_route=\/wp\/v2\/posts\/120\/revisions\/128"}],"wp:attachment":[{"href":"https:\/\/tech.akat.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tech.akat.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=120"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tech.akat.info\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}