Date: Fri, 17 Mar 2000 09:46:35 -0500 From: James FitzGibbon <james@targetnet.com> To: David Malone <dwmalone@maths.tcd.ie> Cc: hackers@freebsd.org Subject: Re: T/TCP friendly inetd change? Message-ID: <20000317094635.B41950@targetnet.com> In-Reply-To: <200003162131.aa50415@salmon.maths.tcd.ie> References: <200003162131.aa50415@salmon.maths.tcd.ie>
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* David Malone (dwmalone@maths.tcd.ie) [000316 16:51]: > I've tried this over my slip link and it does seem to reduce the > number of packets sent by 2 for telnetting to the daytime port. I > also had a look at fetch (the only thing in the tree which uses > MSG_EOF at the moment), which has an option for turning off the > MSG_EOF stuff 'cos some buggy http servers don't like half closed > connections. I don't think this applies in this case 'cos we're > on the server side - not the client side, and the client expects > an EOF anyway. > > Would this be an acceptable patch to inetd? It would be nice to > encourage the use of T/TCP within FreeBSD, as we seem to be the > only people who have it ;-) A couple of points of feedback: - by default, T/TCP is off in the kernel (see src/sys/netinet/tcp_subr.c; around line 85 in my 3.x box). It's also off by default in /etc/defaults/rc.conf - all the "internal" services that inetd provides (including daytime) are turned off by default in /etc/inetd.conf - security conscious people who have read through LINT may turn on the "TCP_DROP_SYNFIN" kernel opt, which breaks T/TCP. I think that this option should be made a sysctl knob just like support for T/TCP before a change like this goes through. That way, any program that wants to support T/TCP can query the value of the knob before deciding if it will support the extensions or not. I like T/TCP (I use it on some of my networked apps for the same reasons you describe), but I don't think that it should be added to a program like inetd which has two default settings that would need to be changed before the T/TCP extensions would ever provide any benefit. More education on T/TCP for both client and server authors is the key here I think; if major web browsers alone would support the extensions, then the massive overhead of HTTP (and the issues that arise from getting around it with HTTP/1.1 KeepAlive and such) would be significantly reduced. -- j. James FitzGibbon james@targetnet.com Targetnet.com Inc. Voice/Fax +1 416 306-0466/0452 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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