A Martian packet is an IP packet which specifies a source or destination address that is reserved for special-use by Internet Assigned Numbers Authority (IANA). If seen on the public internet, these packets cannot actually originate as claimed, or be delivered. However, certain reserved addresses can be routed using multicast, or on private networks, local links, or loopback interfaces, depending on which special-use range they fall within.
Contents
Martian packets commonly arise from IP address spoofing in denial-of-service attacks, but can also arise from network equipment malfunction or misconfiguration of a host.
The name is derived from packet from Mars, a place from which packets clearly cannot originate.
IPv4
Martians include bogons and packets with source or destination addresses within special-use ranges:
IPv6
Martian IPv6 packets include bogons and those having source or destination addresses with the following special-use prefixes:
6to4 is an IPv6 transition technology where the IPv6 address encodes the originating IPv4 address such that every IPv4 /32 has a corresponding, unique IPv6 /48 prefix. Because 6to4 relays use the encoded value for determining the end site of the 6to4 tunnel, 6to4 addresses corresponding to IPv4 martians are not routable and should never appear on the public internet. The 6to4 martians are as follows:
Teredo is another IPv6 transition technology that encodes the originating IPv4 address in the IPv6 address. However, the encoding format encodes the Teredo server address and tunnel information before the IPv4 client address. Thus there is no definable set of prefixes more specific than 2001:0::/32 for Teredo packets with martian end-site addresses. It is, however, possible to spoof Teredo packets with the Teredo server IPv4 address set to a martian. The list of martian Teredo server address prefixes is as follows: