This netblock was owned by PSINet, one of the first and early ISPs.
PSINet was purchased by Cogent many years ago, and thus Cogent became
the owner of the netblock (154.35.0.0/16). At some point IANA, or ARIN,
or AfriNIC, or all of the above decided that the supernet to which
154.35.0.0/16 belongs, 154.0.0.0/8, was allocated to Africa. You can
see that switch here:
Now just because IANA decides to reallocate a /8 doesn't mean everyone
in that /8 loses their IP space. That would be disastrous to all
involved, obviously. So Cogent maintains ownership of 154.35.0.0/16,
while IP space around them is allocated to African providers. Unless
Cogent decides to return 154.35.0.0/16, it will also be so.
So why does 154.0.0.0/8, and 154.35.0.0/16, show up in Mauritius?
This is because the address of AfriNIC is in Mauritius:
OrgName: African Network Information Center
OrgId: AFRINIC
Address: Level 11ABC
Address: Raffles Tower
Address: Lot 19, Cybercity
City: Ebene
StateProv:
PostalCode:
Country: MU
This is the default setting for all IP space allocated to AfriNIC
(Africa). It remains the setting until the IP space is allocated to an
African provider, at which point the whois is updated to reflect the
provider's address. Since 154.35.0.0/16 isn't and won't be allocated to
an African provider, the address remains the address of AfriNIC.