On Aug 12, 2011, at 11:36 PM, Kevin Oberman wrote: > On Fri, Aug 12, 2011 at 2:43 PM, Chip Marshall <c...@2bithacker.net> wrote: >> I've been digging into an issue with SSH throughput and >> discovered that one of the servers involved isn't using RFC1323 >> window scaling and timestamps. >> >> The server is running 7.3-RELEASE-p3, and has >> net.inet.tcp.rfc1323 set to 1. >> >> When connecting out from the server, it sets both Window Scale >> and TimeStamp options in the SYN packet and everything is fine. >> >> When a connection comes into the server with WS and TS set in >> the SYN, the response varies. For port 53 (named) the SYN/ACK >> has WS/TS options. For port 22 (sshd) the SYN/ACK does not have >> WS/TS options, unless the connection is via lo0. >> >> ssh is OpenSSH_5.2p1, compiled from ports with default options. >> >> I'm really at a loss to explain this. >> >> Why does named use RFC1323 on bce0 when sshd doesn't? >> Why does sshd use RFC1323 on lo0 but not on bce0? >> >> I can provide PCAPs of the SYN, SYN/ACK exchanges if that >> will help. > > Try installing security/openssh-portable from ports and enable the HPN > patches.
and let me point out that the relevant patch is in stock HEAD and will ship by default with 9.0. > > As it stands today, openssh locks the window size to a tiny value. > This causes performance over wide area links to be simply terrible. > > Take a look at http://fasterdata.es.net/fasterdata/say-no-to-scp/ for > more information on the issue. As you will see there, window scaling > is the least of the performance issues with openssh. > -- > R. Kevin Oberman, Network Engineer - Retired > E-mail: kob6...@gmail.com > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" -- Bjoern A. Zeeb You have to have visions! Stop bit received. Insert coin for new address family. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
