Date: Tue, 13 Oct 2015 08:06:11 +0100 From: Matthew Seaman <matthew@FreeBSD.org> To: freebsd-questions@freebsd.org Subject: Re: Are udp packets with non-routeable ip addresses valid on public network? Message-ID: <561CAD63.3040103@FreeBSD.org> In-Reply-To: <51462673-A972-40A4-A5AF-163834A154CC@elde.net> References: <561BB03D.1060104@gmail.com> <51462673-A972-40A4-A5AF-163834A154CC@elde.net>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --LHaJWvBbhHLoOvqAxEPfFQqReU41CRNeF Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 12/10/2015 19:32, Terje Elde wrote: > On 12. okt. 2015, at 15:06, Ernie Luzar <luzar722@gmail.com> wrote: >=20 >>> I am receiving unsolicited inbound udp packets with a "to ip >>> address" [10.0.10.1] of a computer on my LAN. Is this valid? > It shouldn't be routes over the internet to you, but it's pretty > common to use between your ISP and yourself, for things like DHCP. > What are the port-numbers? 67/68 or thereabout? Uh... DHCP usually uses just layer-2 (ie. Ethernet) addressing which is a useful feature in a protocol designed to specify host IP addresses... In those cases where you can't have a DHCP server on the same ethernet segment, there is a specific default IP address range for a client host to fall back to in order to make a layer-3 connection to a DHCP server -- which is the 169.254.0.0/16 link-local address range. See RFC 5735. If his ISP was using 10.0.0.0/8 addresses for their customer-facing network segments, I'm pretty sure the OP would have been told about it and hence not be alarmed at seeing that traffic. Cheers, Matthew --LHaJWvBbhHLoOvqAxEPfFQqReU41CRNeF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2 iQJ8BAEBCgBmBQJWHK1jXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXQ2NTNBNjhCOTEzQTRFNkNGM0UxRTEzMjZC QjIzQUY1MThFMUE0MDEzAAoJELsjr1GOGkATFgcP/3mNwhXXBy4F048RkxqpRJMH jdVftwe290sF0MLbRNk0U+S8vm7EgxCsrrZ67pP3PydvbT3uenjM8wdBYIm+sHCp oTyN9LDspEIHTAeRYvkXi4+q7YXsupvB2nwLJ+cif6l7Ncgen25lM1rgkFZb0Vb3 in5YjKOLTZouq4OL1M7GAPZl+IuuAiXSU50yn3GxZcMkMFXZJ7bf4JgymLYt+DFg tky3fh43LEEkSz4AAlq5SFvn1lh/ZSTDfkqdGK/1KjQrM6WrsK4PeHmsVJgwQKjd bJOVCp5YnPl+QG7csa7ZyA+dURn393TRbkEfNB+yT7fRUKlwD9gqYbvLusrtKs8i KM1BvLppKpujJxZA+0iu2Q/20dTL/JGO5i8wH/rD8BTwxI9KLxui1l6ex7sdXPXo Ra7bRFT/EZBv0nE0EX417/LIO7hjtdp3SlJn2iX/rUvUoBBNSpVbW4/c9I/j29UV qm6WaxvMYhl6mgWAYbLuXNAaBd1rlRX9noYI9bFPiQHW3iupvrS3FkPPbiBzx0jt yIw8fkY3iSG1JTsfsVngEHmnVhxndERLP4ivzrs9Api17/cvc2osrUA17ue11PaX 9NEu4ihOoZ62qvyHGUniG/6cWUbxUKmA1sCLFNiNmHr/eAbKVfG1AFw8Wa8ZEZqh I7GWgWrpPApdOPetBZB8 =TSQl -----END PGP SIGNATURE----- --LHaJWvBbhHLoOvqAxEPfFQqReU41CRNeF--
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