Date: Mon, 20 Aug 2007 22:30:12 +0400 From: Igor Sysoev <is@rambler-co.ru> To: freebsd-net@freebsd.org Cc: John-Mark Gurney <gurney_j@resnet.uoregon.edu> Subject: Re: maximum number of outgoing connections Message-ID: <20070820183012.GA27177@rambler-co.ru> In-Reply-To: <20070820165354.GN99491@funkthat.com> References: <20070820151142.GA20183@rambler-co.ru> <20070820165354.GN99491@funkthat.com>
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On Mon, Aug 20, 2007 at 09:53:55AM -0700, John-Mark Gurney wrote:
> Igor Sysoev wrote this message on Mon, Aug 20, 2007 at 19:11 +0400:
> > It seems that FreeBSD can not make more than
> >
> > net.inet.ip.portrange.last - net.inet.ip.portrange.first
> >
> > simultaneous outgoing connections, i.e., no more than about 64k.
> >
> > If I made ~64000 connections 127.0.0.1:XXXX > 127.0.0.1:80, then
> > connect() to an external address returns EADDRNOTAVAIL.
>
> Isn't this more of a limitation of TCP/IP than FreeBSD? because you
> need to treat the srcip/srcport/dstip/dstport as a unique value, and
> in your test, you are only changing one of the four... Have you tried
> running a second we server on port 8080, and see if you can connect
> another ~64000 connections to that port too?
No, TCP/IP limitation is for XXXX in 127.0.0.1:XXXX <> 127.0.0.1:80,
but FreeBSD limits all outgoing connections to the port range, i.e.
local part remote part
127.0.0.1:5000 <> 127.0.0.1:80
192.168.1.1:5000 <> 10.0.0.1:25
can not exist simultaneously, if both connections were started from
local host.
I can not write a simple test-case program, but I can offer simple setup:
cd /usr/ports/www/nginx && make install
create simple nginx.conf:
------------
events {
worker_connections 20000;
}
http {
server {
listen 8080;
server_name test;
location = /loop {
proxy_pass http://127.0.0.1:8080;
error_page 502 = /yahoo;
}
location = /yahoo {
proxy_pass http://www.yahoo.com;
}
}
}
------------
set
sysctl net.inet.ip.portrange.randomized=0
sysctl net.inet.ip.portrange.first=1024
sysctl net.inet.ip.portrange.last=5000
to see the case with default small number of files, sockets, etc.
and run as root:
/usr/local/sbin/nginx -c ./nginx.conf
then ask http://host:8080/loop in browser. nginx will cycle to itslef, then
after first error
2007/08/20 22:05:16 [crit] 29669#0: *94165 connect() to 127.0.0.1:8080 failed (49: Can't assign requested address) while connecting to upstream, client: 127.0.0.1, server: test, URL: "/loop", upstream: "http://127.0.0.1:8080/loop", host: "127.0.0.1:8080"
you will see the second error:
2007/08/20 22:05:16 [crit] 29669#0: *94165 connect() to 87.248.113.14:80 failed (49: Can't assign requested address) while connecting to upstream, client: 127.0.0.1, server: test, URL: "/loop", upstream: "http://87.248.113.14:80/loop", host: "127.0.0.1:8080"
If you think it may be nginx fault, run this under ktrace/truss and see
syscalls.
--
Igor Sysoev
http://sysoev.ru/en/
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