Date: Tue, 27 May 2003 12:13:36 +0900 (JST) From: Kenjiro Cho <kjc@csl.sony.co.jp> To: ashish@symonds.net Cc: freebsd-hackers@freebsd.org Subject: Re: changing the ToS in IP Header Message-ID: <20030527.121336.41645344.kjc@csl.sony.co.jp> In-Reply-To: <1116.203.192.199.30.1053958864.squirrel@secure.symonds.net> References: <1116.203.192.199.30.1053958864.squirrel@secure.symonds.net>
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Ashish Kulkarni wrote: > Is there any way in which I can manipulate the Type of Service (TOS) byte > in the IPv4 header? I need to set the TOS bits on all outgoing packets from > my box to the ISP to a particular pattern (0x02), as otherwise the ISP does > not forward packets. Tell your ISP not to use 0x02; it violates the standard. You may modify the upper 6 bits for an arbitrary value, though. The lower 2 bits of the (now deprecated) TOS field are officially assigned to ECN (RFC3168). 0x02, ECT(0), is used to indicate that the sender is ECN-capable. > I have been able to do this in Linux using the > iptables mangle table: > > http://www.tldp.org/LDP/nag2/x-087-2-firewall.tos.manipulation.html > > but am unable to find a similiar packet-mangling feature in the firewalls > running on FreeBSD...there are rules for matching on TOS pattern, but not > on TOS manipulation. Does anyone know of any tool which can do this? ALTQ supports diffserv and is capable of rewriting the upper 6 bits of the TOS field. http://www.csl.sony.co.jp/~kjc/software.html -Kenjiro
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