Sprint currently filters announcements from its non-customers as follows: RFC 1597 reserved space: accept nothing (**) In the classical "A" space: accept nothing longer than /8 In the classical "B" space: accept nothing longer than /16 in 24/8 space: accept nothing longer than /19 (*) in 195/8: accept nothing longer than /19 in 206/8 - 223/8: accept nothing longer than /19 in 192/8 - 205/8: accept nothing longer than /24 (*) in-line with the IP registries allocation (**) RFC 1597> Private Address Space RFC 1597> The Internet Assigned Numbers Authority (IANA) has reserved RFC 1597> the following three blocks of the IP address space for private RFC 1597> networks: RFC 1597> 10.0.0.0 - 10.255.255.255 RFC 1597> 172.16.0.0 - 172.31.255.255 RFC 1597> 192.168.0.0 - 192.168.255.255 Vab.. On Tue, 15 Apr 1997, Gregory Hersh wrote:

A while ago we had a customer with some routing problems which were caused by Sprint filters (127/8 - 191/8, deny anything longer than /16). When customer called Sprint, he's been told by someone from tech support that 'Sprint doesn't filter anything'. When I called support, I've been told that on 127/8 - 191/8 range Sprint denies anything longer than /16. This morning the same customer called Sprint again, to confirm this information, and been told that for the above range Sprint denies anything longer than /19. It seems like each time you call Sprint support, you hear a different story.

Will someone from Sprint _who knows_ confirm their filtering policy which I have as follows:

0/8 - 126/8, deny subnets of historical A's 127/8 - 191/8, deny anything longer than /16 192/8 - 205/8, deny anything longer than /24 206/8 - 223/8, dney anything longer than /19 192/8 [RIPE], deny anything longer than /19

It would be really nice to have it posted at NANOG web page as well (alas, only AGIS done so).

Thanks,

- Greg -