industry filtering rules

["Lehrer, Neil" <nlehrer () usia gov>]

hi,

sprintlink's filter policy for non sprintlink customers is shown below.  
do other large providers have similar policies?  i am a sprintlink 
customer and am trying to understand how these policies are implemented 
in the industry.  thanks.


ip nums cidr    

RFC 1918                Reserved Addresses Disallow 10.0.0.0/8, 172.16.0.0/12, and 
192.168.0.0/16
0-126   /8      Allow no subnets of historical addresses that were not 
announced in July 1995
127-191         /8      Allow nothing longer than /16 (i.e., /17, /18, /19, etc.)
192-205         /8      Allow nothing longer than /24 (i.e., /25, /26, /27, etc.)
206-223         /8      Allow nothing longer than /19 (i.e., /20, /21, /22, etc.)
195     /8      Allow nothing longer than /19 (i.e., /20, /21, /22, etc.)
24      /8      Allow nothing longer than /19 (i.e., /20, /21, /22, etc.)

*The principal change is that we used to disallow /19s in 206/8-223/8 and 
195/8, and this was not; in line with the minimal allocation units 
performed by the three primary registries




Regards                                     


+++++++++++++++++++++++++++++++++++++++
+ Neil Lehrer                       
+ U.S. Information Agency         
+ Networks and Systems Support Division
+                                   
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+ fax      202 619-3883             
+ internet nlehrer () usia gov         
+                                   
+ "oh what a tangled net we weave   
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