Date: Thu, 1 Aug 1996 07:43:54 -0400 From: jspath@mail.bcpl.lib.md.us (Webmaster Jim) To: freebsd-ports@freebsd.org Subject: Fwd: Lynx and packet size Message-ID: <9608011143.AA07874@mail>
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I read this on the lynx-dev list, and thought someone more knowledgable about FreeBSD could answer the following: On Jul 31, 8:52pm, lynx-dev@sig.net wrote: } From: Klaus Weide <kweide@tezcat.com> } To: Information Help Desk <info@adn.edu.ph> } Cc: Lynx Development <lynx-dev@sig.net> } In-Reply-To: <Pine.LNX.3.91.960801064937.10167A-300000@sili.adn.edu.ph> } Message-Id: <Pine.SUN.3.94.960731202225.12724C-100000@huitzilo.tezcat.com> } Reply-To: lynx-dev@sig.net } On Thu, 1 Aug 1996, Information Help Desk wrote: } > HI !!! } > Our server is running the FreeBSD operating system. We ported } > lynx and have it installed without problems. We tried connecting to } > popular sites such as www.yahoo.com and www.lycos.com and lynx } > successfully connects. However, when we tried sites such as } > www.freebsd.org, ftp.cdrom.com, and www.altavista.digital.com, lynx } > somehow cannot connect. It stops on the message at the screen's bottom } > saying, } > } > HTTP request sent; waiting for response. } > } > And, this goes on forever !!! } > } > We tried lynx running in the Linux operating system, and it was } > able to connect to such sites where lynx in FreeBSD cannot connect to. } } I strongly suspect that this has nothing to do with lynx, but with } the TCP/IP implementation of the operating systems you are using } and/or your machines' network connections. You should hoave the same } kind of problems when using other programs from your FreeBSD machine, } so that connecting to e.g. ftp.cdrom.com with the regular ftp program } shouldn't work either. } } I connected to the five servers you listed from a linux machine and } watched (with tcpdump) the packets that were received from those } servers. The three servers that you list as not working have in } common that they are sending packets longer than the minimum } MTU of 576 bytes. The two servers that worked for you did not. } So I think there lies your problem - your networking path cannot } transmit IP packets greater than 576 bytes, and the FreeBSD OS } does not properly implement either "Path MTU discovery" or } "packet fragmentation and reassambly" (or your router does not } send the required ICMP error messages back to your FreeBSD machine } when it drops a packet that is too big). } } If you have a ping command that allows you to specify a size for } the probe packets (-s option or similar), try it for different } sizes and see what you get. } } I am not familiar with FreeBSD, but probably the easiest solution } (or workaround) would be to find the proper parameters to use for } the "ifconfig" command when the machine boots. On Linux, that } would be something like "ifconfig <...> mtu 576". Or if you } are using PPP or SLIP to connect to the Internet, use the } appropriate options there. } } Klaus }-- End of excerpt from lynx-dev@sig.net -- I don't speak (or work) for the Baltimore County Public Library. They keep telling me, "Shhhhh!"
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