Date: Thu, 22 Apr 2004 17:30:35 +0300 From: Niki Denev <nike_d@cytexbg.com> To: Ruslan Ermilov <ru@freebsd.org> Cc: GiZmen <gizmen@blurp.one.pl> Subject: Re: Changing ttl of incoming packets Message-ID: <cone.1082644235.488773.739.1001@phobos.totalterror.net> References: <20040422095415.GA31126@blurp.one.pl> <20040422131040.GB9359@ip.net.ua>
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This is a MIME GnuPG-signed message. If you see this text, it means that your E-mail or Usenet software does not support MIME signed messages. --=_mimegpg-phobos.totalterror.net-739-1082644235-0001 Content-Type: text/plain; format=flowed; charset="US-ASCII" Content-Disposition: inline Content-Transfer-Encoding: 7bit Ruslan Ermilov writes: > On Thu, Apr 22, 2004 at 11:54:15AM +0200, GiZmen wrote: >> Hello, >> >> Is there any way to change ttl of incoming packet to a lower value ? >> I had tried min-ttl option in pf packet filter but this option only increase >> ttl to a given value when ttl is lower than this value. >> >> I have searched on google and mailing lists but i do not find any answer. >> I am running Freebsd 5.2.1 and i am using pf as my packet filter. >> > You mean, make the IP forwarding decrement the IP TTL more than by one? > > > Cheers, > -- > Ruslan Ermilov > ru@FreeBSD.org > FreeBSD committer i've seen some cable/dsl ips's to do this, they set the IP TTL to 1 on the downlink to the client. (as a lame attempt to stop people sharing their connection) So if one put some sort of gateway on the dsl/cable modem, all the packets it receives are with IP TTL 1, and the gateway will not able to forward them to the internal network....... which is in my opinion 1-st ugly, and 2-nd, easily avoidable with min-ttl for example :) but if pf has min-ttl it seems that max-ttl can be easily added. also i think i've seen somewhere on the net a netgraph module that can modify ttl's and some other things. i think it's name was ng_mangle --niki --=_mimegpg-phobos.totalterror.net-739-1082644235-0001 Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQBAh9cLHNAJ/fLbfrkRAkWXAKC0ZI5aGRoN1eLKjpOq8935IpSqCwCeIT2S 1xLP0e2LZUkCGlY2pW787to= =klBq -----END PGP SIGNATURE----- --=_mimegpg-phobos.totalterror.net-739-1082644235-0001--
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