Chapter 16. ¹âÅ٤ʥͥåȥ¥¯

Table of Contents
¥²¡¼¥È¥¦¥§¥¤¤È¥ë¡¼¥È
NFS
Diskless operation
ISDN

¥²¡¼¥È¥¦¥§¥¤¤È¥ë¡¼¥È

¸¶ºî: Coranth Gryphon . 6 October 1995.

Ìõ: Á°ÅÄ ¹¬ÈÏ . 6 September 1996.

¤¢¤ë·×»»µ¡¤¬Â¾¤Î·×»»µ¡¤ò¤ß¤Ä¤±¤ë¤³¤È¤¬¤Ç¤­¤ë¤è¤¦¤Ë¤¹¤ë¤Ë¤Ï, ¤¢¤ë·×»»µ¡¤«¤é¾¤Î·×»»µ¡¤Ø, ¤É¤Î¤è¤¦¤Ë¤¿¤É¤êÃ夯¤«¤òŬÀڤ˵­½Ò¤¹¤ë¤¿ ¤á¤Î»ÅÁȤߤ¬É¬ÍפǤ¹. ¤³¤Î»ÅÁȤߤò¥ë¡¼¥Æ¥£¥ó¥°¤È¸Æ¤Ó¤Þ¤¹. ``¥ë¡¼¥È(·ÐÏ©)''¤Ï ``destination (ÌÜŪÃÏ) ''¤È ``gateway (¥²¡¼ ¥È¥¦¥§¥¤) ''¤Î 2¤Ä¤Î¥¢¥É¥ì¥¹¤ÎÁȤÇÄêµÁ¤·¤Þ¤¹. ¤¢¤Ê¤¿¤¬ destination ¤Ø¥¢¥¯¥»¥¹¤·¤è¤¦¤È¤·¤¿¾ì¹ç, gateway ¤òÄ̤äÆÁ÷¤é¤ì¤ë¤³¤È¤ò¤³¤Î¥Ú¥¢¤Ï¼¨¤·¤Æ¤¤¤Þ¤¹. destination ¤Ë¤Ï¸Ä¡¹¤Î¥Û¥¹¥È, ¥µ¥Ö¥Í¥Ã¥È, ``¥Ç¥Õ¥©¥ë¥È''¤Î 3¤Ä¤Î ¥¿¥¤¥×¤¬¤¢¤ê¤Þ¤¹. ``¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È''¤Ï¾¤Ø¤Î·ÐÏ©¤¬Å¬ÍѤǤ­¤Ê¤¤ ¾ì¹ç¤Ë»È¤ï¤ì¤Þ¤¹. ¤Î¤Á¤Û¤É¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È¤Ë¤Ä¤¤¤Æ¾¯¤·½Ò¤Ù¤ë¤³¤È ¤¹¤ë¤È¤·¤Æ, ¤³¤³¤Ç¤Ï, ¸Ä¡¹¤Î¥Û¥¹¥È, ¥¤¥ó¥¿¥Õ¥§¡¼¥¹ (``¥ê¥ó¥¯''¤È ¤â¸Æ¤Ð¤ì¤Þ¤¹), ¥¤¡¼¥µ¥Í¥Ã¥È¥Ï¡¼¥É¥¦¥§¥¢¥¢¥É¥ì¥¹¤È¤¤¤¦ 3¤Ä¤Î¥¿¥¤ ¥×¤Î¥²¡¼¥È¥¦¥§¥¤¤Ë¤Ä¤¤¤ÆÀâÌÀ¤·¤Þ¤¹.

Îã

°Ê²¼¤Ë¼¨¤¹ netstat -r ¤Î½ÐÎϤÎÎã¤ò»È¤Ã¤Æ, ¥ë¡¼¥Æ¥£¥ó ¥°¤¬¤¤¤í¤¤¤í¤È°Û¤Ê¤Ã¤Æ¤¤¤ëÍͻҤòÀâÌÀ¤¹¤ë¤³¤È¤Ë¤·¤Þ¤¹.

Destination      Gateway            Flags     Refs     Use     Netif Expire

default          outside-gw         UGSc       37      418      ppp0
localhost        localhost          UH          0      181       lo0
test0            0:e0:b5:36:cf:4f   UHLW        5    63288       ed0     77
10.20.30.255     link#1             UHLW        1     2421
foobar.com       link#1             UC          0        0
host1            0:e0:a8:37:8:1e    UHLW        3     4601       lo0
host2            0:e0:a8:37:8:1e    UHLW        0        5       lo0 =>
host2.foobar.com link#1             UC          0        0
224              link#1             UC          0        0

ºÇ½é¤Î2¹Ô¤Ï¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È(¼¡¤ÎÀá¤Ç¾Ü¤·¤¯ÀâÌÀ¤·¤Þ¤¹)¤È, localhost¤Ø¤Î·ÐÏ©¤ò¼¨¤·¤Æ¤¤¤Þ¤¹.

localhost¤Î¤¿¤á¤Î¥¤¥ó¥¿¥Õ¥§¡¼¥¹ (Netif¤ÎÍó) ¤Ïlo0¤Ç, ¤³¤ì¤Ï¥ë¡¼¥×¥Ð¥Ã¥¯¥Ç¥Ð¥¤¥¹¤È¤·¤ÆÃΤé¤ì¤Æ¤¤¤Þ¤¹. ·ë¶É¤Î¤È¤³¤íÌá¤ë¤À¤±¤Ê¤Î¤Ç, ¤³¤Î destination¤Ø¤Î¤¹¤Ù¤Æ¤Î¥È¥é¥Õ¥£ ¥Ã¥¯¤¬ÆâÉôŪ¤Ë½èÍý¤µ¤ì¤ë¤Î¤Ç¤¢¤Ã¤Æ, LAN ¤ò·Ðͳ¤·¤ÆÁ÷¤é¤ì¤ë¤Î¤Ç¤Ï ¤¢¤ê¤Þ¤»¤ó.

¼¡¤Î¹Ô¤Ç¤Ï0:e0:...¤È¤¤¤¦¥¢¥É¥ì¥¹¤ËÃíÌܤ·¤Þ¤·¤ç¤¦. ¤³¤ì¤Ï¥¤¡¼¥µ¥Í¥Ã¥È¥Ï¡¼¥É¥¦¥§¥¢¥¢¥É¥ì¥¹¤Ç¤¹. FreeBSD¤Ï¼«Æ°Åª¤Ë ¥í¡¼¥«¥ë¤Ê¥¤¡¼¥µ¥Í¥Ã¥È¾å¤ÎǤ°Õ¤Î¥Û¥¹¥È (¤³¤ÎÎã¤Ç¤Ïtest0) ¤ò¸«¤Ä¤±, ¥¤¡¼¥µ¥Í¥Ã¥È¥¤¥ó¥¿¥Õ¥§¡¼¥¹ ed0 ¤Î½ê¤Ë¤½¤Î¥Û¥¹¥È ¤Ø¤Î·ÐÏ©¤òľÀܤĤ±²Ã¤¨¤Þ¤¹. ¥¿¥¤¥à¥¢¥¦¥È»þ´Ö (Expire¤Î Íó) ¤â·ÐÏ©¤Î¥¿¥¤¥×¤È·ë¤Ó¤Ä¤¤¤Æ¤ª¤ê, »ØÄꤵ¤ì¤¿»þ´Ö¤¬·Ð²á¤·¤Æ¤â±þ Åú¤¬¤Ê¤¤¤È¤­¤Ë»ÈÍѤ·¤Þ¤¹. ¤³¤Î¾ì¹ç, ·ÐÏ©¾ðÊó¤Ï¼«Æ°Åª¤Ëºï½ü¤µ¤ì¤Þ ¤¹. ¤³¤ì¤é¤Î¥Û¥¹¥È¤Ï, RIP(Routing Information Protocol) ¤È¤¤¤¦, ºÇû¥Ñ¥¹¤ÎȽÄê¤Ë´ð¤Å¤¤¤Æ¥í¡¼¥«¥ë¥Û¥¹¥È¤Ø¤Î·ÐÏ©¤ò ·èÄꤹ¤ë»ÅÁȤߤò ÍøÍѤ¹¤ë¤³¤È¤Çǧ¼±¤µ¤ì¤Þ¤¹.

¹¹¤Ë, FreeBSD¤Ç¤Ï¥í¡¼¥«¥ë¥µ¥Ö¥Í¥Ã¥È (10.20.30.255 ¤Ï 10.20.30 ¤È¤¤¤¦¥µ¥Ö¥Í¥Ã¥È¤ËÂФ¹¤ë¥Ö¥í¡¼¥É¥­¥ã¥¹¥È¥¢¥É¥ì¥¹¤Ç, foobar.com ¤Ï¤³¤Î¥µ¥Ö¥Í¥Ã¥È¤Ë·ë¤Ó¤Ä¤±¤é¤ì¤Æ¤¤¤ë¥É¥á¥¤¥ó̾) ¤Ø¤Î·ÐÏ©¾ðÊó¤â²Ã¤¨¤ë¤³¤È¤¬¤Ç¤­¤Þ¤¹. link#1¤È¤¤¤¦¤Î ¤Ï, ¤³¤Î·×»»µ¡¤ÎºÇ½é¤Î¥¤¡¼¥µ¥Í¥Ã¥È¥«¡¼¥É¤Î¤³¤È¤ò¤µ¤·¤Þ¤¹. ¤³¤ì¤é ¤Ë¤Ä¤¤¤Æ¤Ï, ²¿¤âÄɲ夥󥿥ե§¡¼¥¹¤¬»ØÄꤵ¤ì¤Æ¤¤¤Ê¤¤¤³¤È¤Ëµ¤¤Å¤¯ ¤Ç¤·¤ç¤¦.

¤³¤ì¤é¤Î2¤Ä¤Î¥°¥ë¡¼¥×(¥í¡¼¥«¥ë¥Í¥Ã¥È¥ï¡¼¥¯¥Û¥¹¥È¤È ¥í¡¼¥«¥ë¥µ¥Ö¥Í¥Ã¥È) ¤ÎξÊý¤È¤â, routed ¤È¸Æ¤Ð¤ì¤ë¥Ç¡¼¥â¥ó¤Ë¤è¤Ã¤Æ¼«Æ°Åª¤Ë ·ÐÏ©¤¬ÀßÄꤵ¤ì¤Þ¤¹. routed ¤òư¤«¤µ¤Ê¤±¤ì¤Ð, ÀÅŪ¤ËÄêµÁ¤·¤¿ (¤Ä¤Þ¤ê¶ñÂÎŪ¤Ë ÀßÄꤷ¤¿) ·ÐÏ©¤Î¤ß¸ºß¤¹¤ë¤³¤È¤Ë¤Ê¤ê¤Þ¤¹.

host1 ¤Î¹Ô¤Ï»ä¤¿¤Á¤Î¥Û¥¹¥È¤Î¤³¤È¤Ç, ¥¤¡¼¥µ¥Í¥Ã¥È¥¢¥É¥ì¥¹¤Ç¼¨¤µ¤ì¤Æ¤¤¤Þ¤¹. Á÷¿®Â¦¤Î¥Û¥¹¥È¤Î¾ì¹ç, FreeBSD¤Ï¥¤¡¼¥µ¥Í¥Ã¥È¥¤¥ó¥¿¥Õ¥§¡¼¥¹¤Ø Á÷¤ë¤Î¤Ç¤Ï¤Ê¤¯, ¥ë¡¼¥×¥Ð¥Ã¥¯¥¤¥ó¥¿¥Õ¥§¡¼¥¹ (lo0)¤ò»È¤¤¤Þ¤¹.

2¤Ä¤¢¤ëhost2¤Î¹Ô¤Ï, ifconfig¤Î¥¨¥¤¥ê¥¢¥¹ (¤³¤Î¤è¤¦¤Ê¤³¤È ¤ò¤¹¤ëÍýͳ¤Ë¤Ä¤¤¤Æ¤Ï ethernet¤Î¾Ï¤ò»²¾È¤·¤Æ¤¯¤À¤µ¤¤) ¤ò»È¤Ã¤¿¤È¤­ ¤Ë¤É¤Î¤è¤¦¤Ë¤Ê¤ë¤«¤ò¼¨¤¹Îã¤Ç¤¹. lo0¤Î¸å¤Ë¤¢¤ë=> ¤Ï, ¥¤¥ó¥¿¥Õ¥§¡¼¥¹¤¬ (¤³¤Î¥¢¥É¥ì¥¹¤¬¥í¡¼¥«¥ë¤Ê¥Û¥¹¥È¤ò»²¾È¤·¤Æ¤¤¤ë¤Î¤Ç) ¥ë¡¼¥×¥Ð¥Ã¥¯¤ò»È¤Ã¤Æ¤¤¤ë¤È¤¤¤¦¤À¤±¤Ç¤Ê¤¯, ¥¨¥¤¥ê¥¢¥¹¤Ë¤Ê¤Ã¤Æ¤¤¤ë¤³¤È¤â ¼¨¤·¤Æ¤¤¤Þ¤¹. ¤³¤Î¤è¤¦¤Ê·ÐÏ©¤Ï¥¨¥¤¥ê¥¢¥¹¤ò¥µ¥Ý¡¼¥È¤·¤Æ¤¤¤ë ¥Û¥¹¥È¤Ë¤Î¤ß¸½¤ì¤Þ¤¹. ¥í¡¼¥«¥ë¥Í¥Ã¥È¥ï¡¼¥¯¾å¤Î¾¤Î¤¹¤Ù¤Æ¤Î¥Û¥¹¥È¤Ç¤Ï ñ¤Ëlink#1¤È¤Ê¤ê¤Þ¤¹.

ºÇ¸å¤Î¹Ô (destination¤¬224¤Î¥µ¥Ö¥Í¥Ã¥È) ¤Ï¥Þ¥ë¥Á¥­¥ã¥¹¥È ¤Ç°·¤¦¤â¤Î¤Ç¤¹¤¬, ¤³¤ì¤Ï¾¤Î¾Ï¤ÇÀâÌÀ¤·¤Þ¤¹.

¾¤ÎÍó¤Ë¤Ä¤¤¤Æ¤Ï Flags ¤Ë¤Ä¤¤¤ÆÀâÌÀ¤¹¤ëɬÍפ¬¤¢¤ê¤Þ¤¹. ¤½¤ì¤¾¤ì¤Î·ÐÏ©¤ÏÍó¤Ë¼¨¤µ¤ì¤Æ¤¤¤ë¤è¤¦¤Ë°ã¤Ã¤¿Â°À­¤ò ¤â¤Ã¤Æ¤¤¤Þ¤¹. °Ê²¼¤Ë¤¤¤¯¤Ä¤«¤Î¥Õ¥é¥°¤È¤³¤ì¤é¤¬²¿¤ò°ÕÌ£¤·¤Æ¤¤¤ë¤«¤ò¼¨¤·¤Þ¤¹.

U Up: ¤³¤Î·ÐÏ©¤Ï¥¢¥¯¥Æ¥£¥Ö¤Ç¤¹.
H Host: ·ÐÏ©¤Î destination¤¬Ã±°ì¤Î¥Û¥¹¥È¤Ç¤¹.
G Gateway: ¤³¤Î destination¤ØÁ÷¤é¤ì¤ë¤È, ¤É¤³¤ØÁ÷¤ì ¤Ð¤è¤¤¤«¤òÌÀ¤é¤«¤Ë¤·¤Æ, ¤½¤Î¥ê¥â¡¼¥È¥·¥¹¥Æ¥à¤ØÁ÷¤é¤ì¤Þ¤¹.
S Static: ¤³¤Î·ÐÏ©¤Ï¥·¥¹¥Æ¥à¤Ë¤è¤Ã¤Æ¼«Æ°Åª¤ËÀ¸À® ¤µ¤ì¤¿¤Î¤Ç¤Ï¤Ê¤¯, ¼êư¤ÇºîÀ®¤µ¤ì¤Þ¤·¤¿.
C Clone: ¥Þ¥·¥ó¤ËÀܳ¤·¤¿¤È¤­¤Ë¤³¤Î·ÐÏ©¤Ë´ð¤Å¤¯ ¿·¤·¤¤·ÐÏ©¤¬ºî¤é¤ì¤Þ¤¹. ¤³¤Î¥¿¥¤¥×¤Î·ÐÏ©¤ÏÄ̾ï¤Ï ¥í¡¼¥«¥ë¥Í¥Ã¥È¥ï¡¼¥¯¤Ç»È¤ï¤ì¤Þ¤¹.
W WasCloned: ¥í¡¼¥«¥ë¥¨¥ê¥¢¥Í¥Ã¥È¥ï¡¼¥¯(Clone) ¤Î·ÐÏ©¤Ë´ð¤Å¤¤¤Æ ¼«Æ°Åª¤ËÀ¸À®¤µ¤ì¤¿·ÐÏ©¤Ç¤¢¤ë¤³¤È¤ò¼¨¤·¤Þ¤¹.
L Link: ¥¤¡¼¥µ¥Í¥Ã¥È¥Ï¡¼¥É¥¦¥§¥¢¤Ø¤Î»²¾È¤ò´Þ¤à ·ÐÏ©¤Ç¤¹.

¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È

¥í¡¼¥«¥ë¥·¥¹¥Æ¥à¤«¤é¥ê¥â¡¼¥È¥Û¥¹¥È¤Ë¥³¥Í¥¯¥·¥ç¥ó¤òÄ¥¤ë ɬÍפ¬¤¢¤ë¾ì¹ç, ´ûÃΤΥѥ¹¤¬Â¸ºß¤¹¤ë¤«¤É¤¦¤«¤ò³Îǧ¤¹¤ë¤¿¤á¤Ë¥ë ¡¼¥Æ¥£¥ó¥°¥Æ¡¼¥Ö¥ë¤ò¥Á¥§¥Ã ¥¯¤·¤Þ¤¹. Åþ㤹¤ë¤¿¤á¤Î¥Ñ¥¹¤òÃΤäƤ¤¤ë¥µ¥Ö¥Í¥Ã¥È¤ÎÆâÉô¤Ë¥ê¥â ¡¼¥È¥Û¥¹¥È¤¬¤¢¤ë¾ì¹ç (Cloned routes), ¥·¥¹¥Æ¥à¤Ï¥¤¥ó¥¿¥Õ¥§¡¼¥¹ ¤«¤éÀܳ¤Ç¤­¤ë¤«¤É¤¦¤«¤ò¥Á¥§¥Ã¥¯¤·¤Þ¤¹.

ÃΤäƤ¤¤ë¥Ñ¥¹¤¬¤¹¤Ù¤ÆÂÌÌܤÀ¤Ã¤¿¾ì¹ç¤Ç¤â, ¥·¥¹¥Æ¥à¤Ë¤Ï ºÇ¸å¤ÎÀڤ껥¤Î ``¥Ç¥Õ¥©¥ë¥È''¥ë¡¼¥È¤¬¤¢¤ê¤Þ¤¹. ¤³¤Î¥ë¡¼¥È¤Ï ¥²¡¼¥È¥¦¥§¥¤¥ë¡¼¥È (ÉáÄ̤ϥ·¥¹¥Æ¥à¤Ë 1¤Ä¤·¤«¤¢¤ê¤Þ¤»¤ó) ¤ÎÆÃÊ̤ʤâ¤Î¤Ç¤¹. ¤½¤·¤Æ, ¥Õ¥é¥°¥Õ¥£¡¼¥ë¥É¤Ïɬ¤º c ¤¬¥Þ¡¼¥¯¤µ¤ì¤Æ¤¤¤Þ¤¹. ¤³¤Î¥²¡¼¥È¥¦¥§¥¤¤Ï, LAN Æâ¤Î¥Û¥¹¥È¤Ë¤È¤Ã ¤Æ, ³°Éô (PPP¤Î¥ê¥ó¥¯¤ò·Ðͳ¤¹¤ë¾ì¹ç¤ä, ¥Ç¡¼¥¿¥é¥¤¥ó¤ËÀܳ¤¹¤ë¥Ï¡¼ ¥É¥¦¥§¥¢¥Ç¥Ð¥¤¥¹¤Ê¤É) ¤ØÄ¾ÀÜÀܳ¤¹¤ë¥Þ¥·¥ó¤¹¤Ù¤Æ¤Î¤¿¤á¤Î¤â¤Î¤Ç¤¹.

³°Éô¤ËÂФ¹¤ë¥²¡¼¥È¥¦¥§¥¤¤È¤·¤Æµ¡Ç½¤¹¤ë¥Þ¥·¥ó¤Ç ¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È ¤òÀßÄꤹ¤ë¾ì¹ç, ¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È¤Ï ¥¤¥ó¥¿¡¼¥Í¥Ã¥È¥µ¡¼¥Ó¥¹¥×¥í¥Ð¥¤¥À (ISP) ¤Î¥µ¥¤¥È¤Î¥²¡¼¥È¥¦¥§ ¥¤¥Þ¥·¥ó¤Ë¤Ê¤ë¤Ç¤·¤ç¤¦.

¤½¤ì¤Ç¤Ï¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È¤Î°ìÎã¤ò¸«¤Æ¤ß¤Þ¤·¤ç¤¦. °ìÈÌŪ¤Ê¹½À®¤ò¼¨¤·¤Þ¤¹.

[Local2]  <--ether-->  [Local1]  <--PPP-->  [ISP-Serv]  <--ether-->  [T1-GW]
    

¥Û¥¹¥È Local1 ¤È¥Û¥¹¥È Local2 ¤ò PPP ¤Ç ISP ¤Î¥¿¡¼¥ß¥Ê¥ë¥µ¡¼¥Ð¤ÈÀܳ¤µ¤ì¤Æ¤¤¤ë¤¢¤Ê¤¿¤Î ¥µ¥¤¥È¤À¤È¤·¤Þ¤¹. ISP ¤Ï¥µ¥¤¥ÈÆâ¤Ë¥í¡¼ ¥«¥ë¤Ê¥Í¥Ã¥È¥ï¡¼¥¯¤ò»ý¤Ã¤Æ¤¤¤Æ, ¤½¤³¤Ë¤Ï¤Þ¤¶¤Þ¤Ê¤â¤Î¤¬¤¢¤ê, ¤¢¤Ê¤¿¤ÎÀܳ¤¹¤ë¥µ¡¼¥Ð¤ä ISP ¤Î¥¤¥ó¥¿¡¼¥Í¥Ã¥È¤Ø¤Î ÀܳÅÀ¤Ç¤¢¤ë¥Ï¡¼¥É¥¦¥§¥¢¥Ç¥Ð¥¤¥¹ (T1-GW) ¤Ê¤É¤¬¤¢¤ê¤Þ¤¹.

¤¢¤Ê¤¿¤Î¥Þ¥·¥ó¤Î¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È¤Ï ¤½¤ì¤¾¤ì¼¡¤Î¤è¤¦¤Ë¤Ê¤ê¤Þ¤¹.

host default gateway interface
Local2 Local1 ethernet
Local1 T1-GW PPP

``¤Ê¤¼ (¤¢¤ë¤¤¤Ï, ¤É¤¦¤ä¤Ã¤Æ) Local1 ¤Î ¥Ç¥Õ¥©¥ë¥È¥²¡¼¥È¥¦¥§¥¤¤òISP¤Î¥µ¡¼¥Ð¤Ç¤Ê¤¯ T1-GW¤Ë¥»¥Ã¥È¤¹¤ë¤Î¤«''¤È¤¤¤¦¼ÁÌ䤬¤è¤¯¤¢¤ê¤Þ¤¹.

¥³¥Í¥¯¥·¥ç¥ó¤Î¥í¡¼¥«¥ë¤Î¦¤Ë¤Ä¤¤¤Æ¤Ï, PPP¤Î¥¤¥ó¥¿¥Õ¥§¡¼¥¹¤Ï ISP¤Î¥í¡¼¥«¥ë¥Í¥Ã¥È¥ï¡¼¥¯¾å¤Î¥¢¥É¥ì¥¹¤òÍѤ¤¤Æ¤¤¤ë¤¿¤á, ISP¤Î¥í¡¼¥«¥ë¥Í¥Ã¥È¥ï¡¼¥¯¾å¤Î¤¹¤Ù¤Æ¤Î¥Þ¥·¥ó¤Ø¤Î·ÐÏ©¤Ï ¼«Æ°Åª¤ËÀ¸À®¤µ¤ì¤Æ¤¤¤Þ¤¹. ¤Ä¤Þ¤ê, ¤¢¤Ê¤¿¤Î¥Þ¥·¥ó¤Ï, ¤É¤Î¤è¤¦¤ËT1-GW ¤Þ¤ÇÆÏ¤¯¤«¤È¤¤¤¦·ÐÏ©¤ò´û¤ËÃΤäƤ¤¤ë¤³¤È¤Ë¤Ê¤ê¤Þ¤¹¤«¤é, ISP¥µ¡¼¥Ð¤ËÇÞ²ðŪ¤Ê¥È¥é¥Õ¥£¥Ã¥¯¤ò¤«¤±¤ëɬÍפϤ¢¤ê¤Þ¤»¤ó.

ºÇ¸å¤Ë¤Ê¤ê¤Þ¤·¤¿¤¬, °ìÈÌŪ¤Ë¥í¡¼¥«¥ë¥Í¥Ã¥È¥ï¡¼¥¯¤Ç¤Ï ...1 ¤È¤¤¤¦¥¢¥É¥ì¥¹¤ò¥²¡¼¥È¥¦¥§¥¤¥¢¥É¥ì¥¹¤È¤·¤Æ»È¤¤¤Þ¤¹. ¤Ç¤¹¤«¤é (Ʊ¤¸Îã¤òÍѤ¤¤Þ¤¹), ¤¢¤Ê¤¿¤Îclass-C¤Î¥¢¥É¥ì¥¹¶õ´Ö¤¬ 10.20.30¤Ç ISP¤¬10.9.9¤òÍѤ¤¤Æ¤¤¤ë¾ì¹ç, ¥Ç¥Õ¥©¥ë¥È¥ë¡¼¥È¤Ï¼¡¤Î¤è¤¦¤Ë¤Ê¤ê¤Þ¤¹.

Local2 (10.20.30.2)             -->  Local1 (10.20.30.1)
Local1 (10.20.30.1, 10.9.9.30)  -->  T1-GW (10.9.9.1)
      

¥Þ¥ë¥Á¥Û¡¼¥à¥Û¥¹¥È

¤³¤³¤Ç°·¤¦¤Ù¤­Â¾¤Î¥¿¥¤¥×¤ÎÀßÄ꤬¤¢¤ê¤Þ¤¹. ¤½¤ì¤Ï2¤Ä¤Î°Û¤Ê¤ë¥Í¥Ã¥È¥ï¡¼ ¥¯¤Ë¤Þ¤¿¤¬¤ë¥Û¥¹¥È¤Ç¤¹. µ»½ÑŪ¤Ë¤Ï¥²¡¼¥È¥¦¥§¥¤¤È¤·¤Æµ¡Ç½¤¹¤ë¥Þ¥·¥ó (¾å ¤ÎÎã¤Ç¤Ï PPP¥³¥Í¥¯¥·¥ç¥ó¤òÍѤ¤¤Æ¤¤¤Þ¤¹) ¤Ï¥Þ¥ë¥Á¥Û¡¼¥à¥Û¥¹¥È¤Ç ¤¹. ¤·¤«¤·¼ÂºÝ¤Ë¤Ï¤³¤Î¸ÀÍÕ¤Ï, 2¤Ä¤Î¥í¡¼¥«¥ë¥¨¥ê¥¢¥Í¥Ã¥È¥ï¡¼¥¯¾å¤Î¥µ ¥¤¥È¤Ç¤¢¤ë¥Þ¥·¥ó¤ò»Ø¤¹¸ÀÍդȤ·¤Æ¤Î¤ß»È¤ï¤ì¤Þ¤¹.

2Ëç¤Î¥¤¡¼¥µ¥Í¥Ã¥È¥«¡¼¥É¤ò»ý¤Ä¥Þ¥·¥ó¤¬, Ê̤Υµ¥Ö¥Í¥Ã¥È ¾å¤Ë¤½¤ì¤¾¤ì¥¢¥É¥ì¥¹¤ò»ý¤Ã¤Æ¤¤¤ë¾ì¹ç¤¬¤¢¤ê¤Þ¤¹. ¤¢¤ë¤¤¤Ï, ¥¤¡¼¥µ¥Í¥Ã¥È¥«¡¼¥É¤ò1Ëç»ý¤Ã¤Æ¤¤¤ë¥Þ¥·¥ó¤Ç, ifconfig¤Î¥¨¥¤¥ê¥¢¥¹¤ò»È¤Ã¤Æ¤¤¤ë¤«¤â¤·¤ì¤Þ¤»¤ó. ʪÍýŪ¤Ëʬ¤«¤ì¤Æ¤¤¤ë2¤Ä¤Î¥¤¡¼¥µ¥Í¥Ã¥È¤Î¥Í¥Ã¥È¥ï¡¼¥¯¤¬»È¤ï¤ì¤Æ ¤¤¤ë¤Ê¤é¤ÐÁ°¼Ô¤¬ÍѤ¤¤é¤ì¤Þ¤¹. ¸å¼Ô¤Ï, ʪÍýŪ¤Ë¤Ï1¤Ä¤Î¥Í¥Ã¥È¥ï ¡¼¥¯¥»¥°¥á¥ó¥È¤Ç, ÏÀÍýŪ¤Ë¤Ïʬ¤«¤ì¤Æ¤¤¤ë 2¤Ä¤Î¥µ¥Ö¥Í¥Ã¥È¤È¤¹¤ë ¾ì¹ç¤ËÍѤ¤¤é¤ì¤Þ¤¹.

¤É¤Á¤é¤Ë¤·¤Æ¤â, ¤³¤Î¥Þ¥·¥ó¤¬¤ª¸ß¤¤¤Î¥µ¥Ö¥Í¥Ã¥È¤Ø¤Î¥²¡¼¥È¥¦¥§¥¤ (inbound route) ¤È¤·¤ÆÄêµÁ¤µ¤ì¤Æ¤¤¤ë¤³¤È¤¬Ê¬¤«¤ë¤è¤¦¤Ë, ¤ª¤Î¤ª ¤Î¤Î¥µ¥Ö¥Í¥Ã¥È¤Ç¥ë¡¼¥Æ¥£¥ó¥°¥Æ¡¼¥Ö¥ë¤òÀßÄꤷ¤Þ¤¹. ¤³¤Î¥Þ¥·¥ó¤¬ 2 ¤Ä¤Î¥µ¥Ö¥Í¥Ã¥È¤Î´Ö¤Î¥Ö¥ê¥Ã¥¸¤È¤·¤ÆÆ°ºî¤¹¤ë¤È¤¤¤¦¹½À®¤Ï, ¥Ñ¥± ¥Ã¥È¤Î¥Õ¥£¥ë¥¿¥ê¥ó¥°¤ò¼ÂÁõ¤¹¤ëɬÍפ¬¤¢¤ë¾ì¹ç¤ä, °ìÊý¸þ¤Þ¤¿¤ÏÁÐ Êý¸þ¤Î¥Õ¥¡¥¤¥¢¥¦¥©¡¼¥ë¤òÍøÍѤ·¤¿¥»¥­¥å¥ê¥Æ¥£¤ò¹½ÃÛ¤¹¤ë¾ì¹ç¤Ë¤è ¤¯ÍѤ¤¤é¤ì¤Þ¤¹.

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