I have noted that the routing table in Linux is orderly by the length of the netid given in the NETMASK. Is this merely fortuitous or do the TCP/IP protocols state that networks with a bigger netid must match before than networks with a smaller netid Since the addressing scheme allows having networks like the following: 128.0.192.0/18 128.0.0.0/16 the order in which these entries appear in the routing table matters because the computers in the network 128.0.192.0/18 match both entries. #BEGIN TRICKY It could be used to have various subnets (like is 128.0.192.0/18 in this case) and a default network to which deliver the remaining datagrams, though computer hosts 128.0.0.0 through 128.0.191.255 would need to add entries in their routing tables to contemplate the other subnets (128.0.192.0 through 128.0.255.255 hosts network in this case) and for not to deliver datagrams in the 128.0.0.0 through 128.0.191.255 network to the gateway, since they are not for those subnets. #END TRICKY The main questions are: First: Is the order in the Linux routing table on purpouse? Is it a TCP/IP specification? This feature (the order in the routing table) would be innecessary if subnetting was done in an uniform way: network addresses do not match several entries in a routing table. Second: Is it common practice to exploit this feature as shown in the above subnetting example or it should be avoided? TIA Zacarias - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
