Date: Thu, 30 Nov 2017 17:39:37 +0000 From: Rick Miller <vmiller@hostileadmin.com> To: "freebsd-doc@freebsd.org" <freebsd-doc@freebsd.org>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: net.inet.ip.portrange and The FreeBSD Handbook Message-ID: <CAHzLAVHt%2B0bVVQ17T9HrRRxU4pdN8vRcoksju806WjqmSTzzFQ@mail.gmail.com>
next in thread | raw e-mail | index | archive | help
Hi all, I found The FreeBSD Handbook[1] had this to say regarding net.inet.ip.portrange.* sysctl variables: =E2=80=9CThe net.inet.ip.portrange.* sysctl(8) variables control the port n= umber ranges automatically bound to TCP and UDP sockets. There are three ranges: a low range, a default range, and a high range. Most network programs use the default range which is controlled by net.inet.ip.portrange.first and net.inet.ip.portrange.last, which default to 1024 and 5000, respectively. Bound port ranges are used for outgoing connections and it is possible to run the system out of ports under certain circumstances. This most commonly occurs when running a heavily loaded web proxy. The port range is not an issue when running a server which handles mainly incoming connections, such as a web server, or has a limited number of outgoing connections, such as a mail relay. For situations where there is a shortage of ports, it is recommended to increase net.inet.ip.portrange.last modestly. A value of 10000, 20000 or 30000 may be reasonable. Consider firewall effects when changing the port range. Some firewalls may block large ranges of ports, usually low-numbered ports, and expect systems to use higher ranges of ports for outgoing connections. For this reason, it is not recommended that the value of net.inet.ip.portrange.first be lowered.=E2=80=9D FreeBSD 11.1 deploys values contrary to those above: # uname -sr FreeBSD 11.1-STABLE # sysctl net.inet.ip.portrange net.inet.ip.portrange.randomtime: 45 net.inet.ip.portrange.randomcps: 10 net.inet.ip.portrange.randomized: 1 net.inet.ip.portrange.reservedlow: 0 net.inet.ip.portrange.reservedhigh: 1023 net.inet.ip.portrange.hilast: 65535 net.inet.ip.portrange.hifirst: 49152 net.inet.ip.portrange.last: 65535 net.inet.ip.portrange.first: 10000 net.inet.ip.portrange.lowlast: 600 net.inet.ip.portrange.lowfirst: 1023 A commit in March 2008[2] sets net.inet.ip.portrange.first and last to 10000 and 65535 respectively. It=E2=80=99s apparently obvious The FreeBSD H= andbook includes obsolete guidelines. This raises the question =E2=80=9Chow does th= is change the advice given in The Handbook?=E2=80=9D PR 223997 is opened to have The Handbook updated. [1] https://www.freebsd.org/doc/handbook/configtuning-kernel-limits.html [2] https://svnweb.freebsd.org/base/stable/11/sys/netinet/in.h?revision=3D17680= 5&view=3Dmarkup =E2=80=94 Rick <703-581-3068> --=20 Take care Rick Miller
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAHzLAVHt%2B0bVVQ17T9HrRRxU4pdN8vRcoksju806WjqmSTzzFQ>