Date: Tue, 12 Jun 2001 10:23:27 +0300 From: Ruslan Ermilov <ru@FreeBSD.ORG> To: William Wong <willwong@samurai.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: man 4 blackhole Message-ID: <20010612102327.E95192@sunbay.com> In-Reply-To: <006801c0f2f5$98bce740$0300a8c0@anime.ca>; from willwong@samurai.com on Tue, Jun 12, 2001 at 12:10:20AM -0400 References: <006801c0f2f5$98bce740$0300a8c0@anime.ca>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Jun 12, 2001 at 12:10:20AM -0400, William Wong wrote: > Hi there, > > I'm looking at the man page and I don't see a difference between setting > net.inet.tcp.blackhole, to either 1 or 2. Here's a section from the > manpage. > > "Normal behaviour, when a TCP SYN segment is received on a port where > there is no socket accepting connections, is for the system to return a > RST segment, and drop the connection. The connecting system will see > this as a "Connection reset by peer". By turning the TCP black hole MIB > on to a numeric value of one, the incoming SYN segment is merely dropped, ^^^^^^^^^^^ > and no RST is sent, making the system appear as a blackhole. By setting > the MIB value to two, any segment arriving on a closed port is dropped ^^^^^^^^^^^ > without returning a RST. This provides some degree of protection against > stealth port scans." > > Since I'm sure option 2 isn't there for no reason, I must be interpreting > this wrong. > > Anyone know the difference? > > Regards, > - Will > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message -- Ruslan Ermilov Oracle Developer/DBA, ru@sunbay.com Sunbay Software AG, ru@FreeBSD.org FreeBSD committer, +380.652.512.251 Simferopol, Ukraine http://www.FreeBSD.org The Power To Serve http://www.oracle.com Enabling The Information Age To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010612102327.E95192>