Calling Cogent, Avantel (AS 6503) and Axtel (AS 14000): Axtel is announcing 100.10.10.0/24, which is within the 100.0.0.0/8 block, which is unallocated according to
http://www.iana.org/assignments/ipv4-address-space/
I am seeing this from two of my transit providers, the common AS path is:
174 6503 6503 6503 6503 6503 14000
Prefix filtering is a good thing, please do it!
Steinar Haug, Nethelp consulting, sth...@nethelp.no
