What do you have the listen queue limit set for? What is the kern.somaxconn sysctl variable set to?
-DG David Greenman Co-founder/Principal Architect, The FreeBSD Project - http://www.freebsd.org Creator of high-performance Internet servers - http://www.terasolutions.com >I'm benchmarking the performance of a server application on various >platforms. To do so, I've developed a program on FreeBSD 3.x to generate >heavy loads. This program can, for example, generate 200 simultaneous >connections to the server and process them all appropriately, and I have >it running on a bunch of machines to simulate high load on the server. > >However, I'm running into an unexpected problem on a server running >FreeBSD 3.2-RELEASE. If a single client opens 200 simultaneous >connections to the FreeBSD server, all but 30 to 40 of those get an >immediate "Connection refused". If a whole row of clients open 200 >simultaneous connections each, they still get only 30 to 40 each, but the >server is now accepting upwards of 200 connections all at once. This >seems to indicate that it's not a server load question, but rather that >the server will not accept more than ~40 connections at once from the same >client. > >I've tried the same test using the FreeBSD clients against a Solaris >server, and the Solaris server accepts all 200 connections from each >client machine without refusing any connections, so I'm sure it's not on >the client end. > >A fellow admin suggested that my load simulation program quite possibly >looks like a SYN attack and FreeBSD might be rejecting it for that reason. >Since Solaris doesn't have the same SYN attack protection, that would >account for the difference. > >If this is the case, how would I disable the SYN attack protection for >these tests? Or is it something else limiting FreeBSD? > >For reference, the FreeBSD server has a custom kernel compiles with >MAXUSERS set to 512, and other performance enhancements I've gleaned off >these lists. > >Thanks, > >Ken Bolingbroke >hac...@bolingbroke.com > > > >To Unsubscribe: send mail to majord...@freebsd.org >with "unsubscribe freebsd-hackers" in the body of the message To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
