Linux Certif

Toute la documentation sur la certification Linux LPI

icmp

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icmp, IPPROTO_ICMP - Linux IPv4 ICMP ¥«¡¼¥Í¥ë¥â¥¸¥å¡¼¥ë

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¤³¤Î¥«¡¼¥Í¥ë¥â¥¸¥å¡¼¥ë¤Ï RFC 792 ¤ÇÄêµÁ¤µ¤ì¤Æ¤¤¤ë Internet Control Message Protocol ¤ò¼ÂÁõ¤·¤¿¤â¤Î¤Ç¤¢¤ë¡£ ¤³¤Î¥×¥í¥È¥³¥ë¤Ï¥¨¥é¡¼¾õ¶·¤òÃΤ餻¤¿¤ê¿ÇÃǤò¹Ô¤¦¤¿¤á¤ËÍѤ¤¤é¤ì¤ë¡£ ¥æ¡¼¥¶¡¼¤Ï¤³¤Î¥â¥¸¥å¡¼¥ë¤È¤ÏľÀܤˤÏÄÌ¿®¤Ç¤­¤Ê¤¤¡£ ¤³¤Î¥â¥¸¥å¡¼¥ë¤Ï¥«¡¼¥Í¥ë¤Î¾¤Î¥×¥í¥È¥³¥ë¤ÈÄÌ¿®¤·¡¢ ¤½¤ì¤é¤Î¥×¥í¥È¥³¥ë¤¬ ICMP ¥¨¥é¡¼¤ò¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¥ì¥¤¥ä¤ËÅϤ¹¡£ ¥«¡¼¥Í¥ë¤Î ICMP ¥â¥¸¥å¡¼¥ë¤Ï ICMP ¥ê¥¯¥¨¥¹¥È¤ËÂФ¹¤ë±þÅú¤â¹Ô¤¦¡£

raw ¥½¥±¥Ã¥È¤ò¥×¥í¥È¥³¥ë IPPROTO_ICMP ¤Ç¥ª¡¼¥×¥ó¤¹¤ì¤Ð¡¢ ¥æ¡¼¥¶¡¼¥×¥í¥È¥³¥ë¤Ï¥í¡¼¥«¥ë¤Ê¥½¥±¥Ã¥ÈÁ´¤Æ¤ËÂФ¹¤ë ICMP ¥Ñ¥±¥Ã¥È¤ò¼õ¿®¤¹¤ë¤³¤È¤¬¤Ç¤­¤ë¡£ ¾ÜºÙ¤Ï raw(7) ¤ò»²¾È¤Î¤³¤È¡£ ¥½¥±¥Ã¥È¤ËÅϤµ¤ì¤ë ICMP ¥Ñ¥±¥Ã¥È¤Î¥¿¥¤¥×¤Ï ICMP_FILTER ¥ª¥×¥·¥ç¥ó¤Ë¤è¤Ã¤Æ¥Õ¥£¥ë¥¿¡¼¤Ç¤­¤ë¡£ ICMP ¥Ñ¥±¥Ã¥È¤Ï (¤¿¤È¤¨¥æ¡¼¥¶¡¼¥½¥±¥Ã¥È¤ËÅϤµ¤ì¤ë¾ì¹ç¤Ç¤â)¡¢ ¾ï¤Ë¥«¡¼¥Í¥ë¤Ë¤è¤Ã¤Æ (¤â) ½èÍý¤µ¤ì¤ë¡£

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sysctl

ICMP ¤Ç¤Ï¡¢¤¤¤¯¤Ä¤«¤Î¥°¥í¡¼¥Ð¥ë¤Ê IP ¥Ñ¥é¥á¡¼¥¿¤ò sysctl ¤òÄ̤·¤ÆÀßÄꤹ¤ë¤³¤È¤¬¤Ç¤­¤ë¡£ ¤³¤ì¤é¤Î sysctl ¤Ø¥¢¥¯¥»¥¹¤¹¤ë¤Ë¤Ï¡¢ /proc/sys/net/ipv4/* ¥Õ¥¡¥¤¥ë¤òÆɤ߽ñ¤­¤¹¤ëÊýË¡¤È¡¢¥¤¥ó¥¿¡¼¥Õ¥§¡¼¥¹¤ËÂФ·¤Æ sysctl(2) ¤òÍѤ¤¤ëÊýË¡¤¬¤¢¤ë¡£ ¤³¤ì¤é¤Î sysctl ¤Î¤Û¤È¤ó¤É¤ÏÆÃÄê¤Î ICMP ¥¿¥¤¥×¤ËÂФ¹¤ë¥ì¡¼¥ÈÀ©¸Â (rate limitation) ¤Ç¤¢¤ë¡£ Linux 2.2 ¤Ï ICMP ¤ÎÀ©¸Â¤Ë¥È¡¼¥¯¥ó¡¦¥Ð¥±¥Ã¥È¡¦¥Õ¥£¥ë¥¿ (token bucket filter) ¤òÍѤ¤¤ë¡£ ¤½¤ì¤¾¤ì¤ÎÃͤϡ¢¥Ð¡¼¥¹¥È¤Î¸å¤Ë¥È¡¼¥¯¥ó¡¦¥Ð¥±¥Ã¥È¡¦¥Õ¥£¥ë¥¿¤¬¥¯¥ê¥¢ ¤µ¤ì¤ë¤Þ¤Ç¤Î¥¿¥¤¥à¥¢¥¦¥È¤òÉÃñ°Ì¤Çɽ¤·¤¿¤â¤Î¤Ç¤¢¤ë¡£ºÇ¾®Ã±°Ì(jiffy)¤Ï ¥·¥¹¥Æ¥à°Í¸¤Îñ°Ì¤Ç x86 ¥·¥¹¥Æ¥à¤ÏÄ̾ï 10ms¡¢alpha ¤ä IA64 ¤Ç¤Ï 1ms ¤Ç¤¢¤ë¡£

icmp_destunreach_rate

ICMP ÉÔã¥Ñ¥±¥Ã¥È (Destination Unreachable packet) ¤òÁ÷¤ëºÇÂç¥ì¡¼¥È¡£ ¤³¤ì¤ÏÆÃÄê¤Î¥ë¡¼¥È¤Þ¤¿¤Ï¹Ô¤­Àè¤Ë¥Ñ¥±¥Ã¥È¤òÁ÷¿®¤¹¤ë¥ì¡¼¥È¤òÀ©¸Â¤¹¤ë¡£ ¤³¤ÎÀ©¸Â¤Ï¡¢ path MTU discovery ¤ËɬÍ×¤Ê ICMP_FRAG_NEEDED ¥Ñ¥±¥Ã¥È¤ÎÁ÷¿®¤Ë¤Ï±Æ¶Á¤·¤Ê¤¤¡£

icmp_echo_ignore_all

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icmp_echo_ignore_broadcasts

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icmp_echoreply_rate

ICMP_ECHOREQUEST ¥Ñ¥±¥Ã¥È¤Ë±þÅú¤¹¤ë ICMP_ECHOREPLY ¥Ñ¥±¥Ã¥È¤ÎºÇÂçÁ÷¿®¥ì¡¼¥È¡£

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ICMP_TIME_EXCEEDED ¥Ñ¥±¥Ã¥È¤ÎºÇÂçÁ÷¿®¥ì¡¼¥È¡£ ¤³¤ì¤é¤Î¥Ñ¥±¥Ã¥È¤Ï¥Ñ¥±¥Ã¥È¤¬¤¢¤Þ¤ê¤Ë¿¤¯¤Î hop ¤òÄ̲ᤷ¤¿¾ì¹ç¤Ë¡¢ ¥ë¡¼¥×¤òËɤ°¤¿¤á¤ËÁ÷¤é¤ì¤ë¡£

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ICMP_SOURCE_QUENCH ¤Ï Linux 2.2 ¤Çºï½ü¤µ¤ì¤¿¡£

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ICMP_TIMESTAMP ¤«¤éÊÖ¤µ¤ì¤ë 64 ¥Ó¥Ã¥È¤Î¥¿¥¤¥à¥¹¥¿¥ó¥×¤Ï¡¢ 1970 ǯ 1 ·î 1 Æü¤«¤é¤Î·Ð²á»þ´Ö¤ò¥ß¥êÉÃñ°Ì¤Çɽ¤·¤¿¤â¤Î¤Ç¤¢¤ë¡£

Linux ICMP ¤Ï ICMP ¤òÁ÷¤ë¤¿¤á¤ËÆâÉô¤Ç raw ¥½¥±¥Ã¥È¤òÍѤ¤¤ë¡£ raw ¥½¥±¥Ã¥È¤Ï netstat(8) ¤Î½ÐÎÏ¤Ë 0 inode ¤È¤·¤Æ½ÐÎϤµ¤ì¤ë¡£

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ip(7)

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