[c-nsp] Prefix-list help

[Chris O'Hair]

Hello,

This morning, while checking for an internal route to 192.168.1.1, I
noticed a rather large supernet was advertised from one of our
upstream ISPs:

#sh ip bgp 192.168.1.1
BGP routing table entry for 128.0.0.0/1, version 3286876

I have a prefix-list for incoming updates to filter out bogons but its
not checking for minimum lengths.  Can someone help me out with a
prefix-list statement that will block this nastiness but not remove
any useful aggregation?

Thanks,
Chris