From owner-freebsd-questions@freebsd.org Fri Jun 24 15:34:13 2016 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8D2CCB80814 for ; Fri, 24 Jun 2016 15:34:13 +0000 (UTC) (envelope-from web@3dresearch.com) Received: from smtpb.telissant.net (smtpb.telissant.net [199.233.230.156]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 66EE01BF0 for ; Fri, 24 Jun 2016 15:34:12 +0000 (UTC) (envelope-from web@3dresearch.com) Received: from barrida.3dresearch.com (localhost [127.0.0.1]) by smtpb.telissant.net (Postfix) with ESMTP id 6BAE23ACDF for ; Fri, 24 Jun 2016 11:28:14 -0400 (EDT) X-Virus-Scanned: amavisd-new at telissant.net Received: from smtpb.telissant.net ([127.0.0.1]) by barrida.3dresearch.com (barrida.3dresearch.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4K9cL5a_wA1R for ; Fri, 24 Jun 2016 11:27:54 -0400 (EDT) Received: from almavivazfs.3dresearch.com (unknown [71.112.241.83]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by smtpb.telissant.net (Postfix) with ESMTPSA id 0C5CF3ACF1 for ; Fri, 24 Jun 2016 11:27:54 -0400 (EDT) Received: from almavivazfs.3dresearch.com (localhost [127.0.0.1]) by almavivazfs.3dresearch.com (Postfix) with SMTP id 69A30AAC68F for ; Fri, 24 Jun 2016 11:27:53 -0400 (EDT) Date: Fri, 24 Jun 2016 11:26:59 -0400 From: Janos Dohanics To: FreeBSD Questions Subject: LAN slow or dead, intermittently Message-Id: <20160624112659.a9fd454b8d05166befb5876d@3dresearch.com> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.29; amd64-portbld-freebsd10.3) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jun 2016 15:34:13 -0000 Hello List, Please help me figure out what makes my LAN intermittently slow or just about dead. The LAN consists of a pfSense router (m1n1wall), a Netgear GS724T switch, a recently installed FreeBSD 10.3 machine, several Windows 7 Pro machines, androids and iPhones, and a Brother printer, altogether between a dozen and 2 dozen networked devices. There are no local servers on the network, so as far as I can tell, most traffic to and from the local nodes is with the internet Desktops have wired connections (100 MB or 1 GB NICs), but the phones and most laptops are connected by WiFi. WiFi is provided by a Linksys E1500 configured to work only as a WiFi AP. There is also a Linksys RE4000W WiFi extender on the network. The FreeBSD machine, the printer, the switch, the E1500 and RE4000W WiFis have static IP addresses. Most of the Windows machines have reserved DHCP addresses, the rest are unreserved DHCP. pfSense is providing the DHCP server. I started to investigate the problem using mtr(8) which runs every 10 minutes. Several times in my testing, the average RTT between the FreeBSD machine (10.10.11.252) and the router's LAN interface (10.10.11.1) was hundreds of milliseconds. Also, several times, 1 out of the 10 packets is lost, but whenever this packet loss occurs, RTTs are mostly 0.1 or 0.2 ms, but always less than 1 ms. Pinging various hosts on the LAN at times is in the 10s of milliseconds or higher. Using my FreeBSD laptop and the FreeBSD machine, I tested the LAN with netperf(1) which showed over 80 Mbit/s in good times but also less than 1 Mbit/s at other times. During off-hours, I have disconnected and then reconnected computers one by one, but could not identify any as the culprit. Replaced the switch and patch cables - the problem is still there... intermittently. None of the Windows computers seems to have any malware which might flood the network. I looked at pftop, and traffic seems to be legit - but how could I see all LAN traffic and possibly correlate it with the slowdown? Could this be caused by a broken networking hardware? How would I identify that? What is the intelligent way to track down this problem? Please advise. -- Janos Dohanics