Routing problems

[LiuJiusheng]

John-Mark Gurney wrote:
> LiuJiusheng wrote this message on Wed, Oct 24, 2007 at 15:41 +0800:
>   
>> Hello all:
>> 	I have found something interesting in FreeBSD routing. This is a test environment, which is not used in reality(perhaps meaningless).	
>> 	
>>                 | host |-------|   router1  |----------| router2 |
>> 	         2.2.2.2     2.2.2.1      6.6.6.1   6.6.6.2  X.X.X.X
>> 			(All run FreeBSD OS)
>>
>> 	Two routes is added to the router1. (4.4.4.0/24 6.6.6.2) and (6.6.6.0/24 2.2.2.2).Then the routing table look this:
>> 	Destination        Gateway            Flags    Refs      Use  Netif Expire     
>> 	2                  link#3             UC          0        0       
>> 	2.2.2.1            00:0c:29:67:a5:88  UHLW        0        4       
>> 	2.2.2.2            00:09:6b:42:94:b7  UHLW        1        2          1068
>> 	4.4.4/24           6.6.6.2            UGS         0       38       
>> 	6                  link#4             UC          0        0       
>> 	6.6.6/24           2.2.2.2            UGS         1        0     
>>
>> 	At this time, route 4.4.4.0 can not be used. When ping 4.4.4.4, the machine prints: sent to: Invalid argument. If I remove the route 6.6.6.0/24, then all become correct.
>>     
>
> You need to have the gateway for 4.4.4/24 be 2.2.2.2...  The routing
> code isn't smart enough to follow the trail through 6.6.6/24 to get to
> 2.2.2.2....
>
>   
Linux takes 6.6.6.2 as gateway for route 4.4.4/24. But some Oses have the gateway 2.2.2.2. (treat 4.4.4/24 as a recursive route).
Is there any standard for this?