From owner-freebsd-questions@freebsd.org Wed Jun 13 01:28:53 2018 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 11140101422A for ; Wed, 13 Jun 2018 01:28:53 +0000 (UTC) (envelope-from rfg@tristatelogic.com) Received: from outgoing.tristatelogic.com (segfault.tristatelogic.com [69.62.255.118]) by mx1.freebsd.org (Postfix) with ESMTP id 97DCE83F53 for ; Wed, 13 Jun 2018 01:28:52 +0000 (UTC) (envelope-from rfg@tristatelogic.com) Received: from segfault-nmh-helo.tristatelogic.com (localhost [127.0.0.1]) by segfault.tristatelogic.com (Postfix) with ESMTP id 564203AEF8 for ; Tue, 12 Jun 2018 18:28:45 -0700 (PDT) From: "Ronald F. Guilmette" To: freebsd-questions@freebsd.org Subject: NIC locks up for no reason (?) Date: Tue, 12 Jun 2018 18:28:45 -0700 Message-ID: <23524.1528853325@segfault.tristatelogic.com> X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Jun 2018 01:28:53 -0000 I am experiencing a really rather odd problem, and could use some helpful advice. I'm sure there is a good explanation for why this is happening, but at the moment I have no idea what it is. More than a month ago, I got myself a shiny new VM on one of the many providers of such on the Internet. I loaded up 11.1-RELEASE-p9, fiddled sshd so that it would run on a somewehat obscure unused port. Anyway, after doing the above things, all was running well, and exactly as expected for some time thereafter. (I have mostly just been using the box for some obscure research purposes.) I never set up any kind of filewall on the thing because frankly, I was doing so little with the box I didn't think I'd need one. Recently, I decided to install and run apache24, which I did. I configured that also to run on a non-standard port, since my intent was that the web stuff it would be serving up would only be stuff that I and perhaps a few close friends would look it. Apache started up just fine, and I was able to acces web content on the box via the non-standard port, from a system elsewhere on the Internet. No problem. Anyway, now it appears that the NIC on this VM system is effectively locking up from time to time, and I have no idea how to even begin to debug this problem. This happened a few days ago, and I managed to get to a virtual console, I logged in as root, and then I rebooted FreeBSD on the VM and again, all was well... for awhile. When this problem occurred before, it appeared that the (virtual) NIC of the VM was not accepting -any- packets from outside. Now the NIC has locked up again. Once again, from the outside it appears that it isn't responding to pings. or to traceroutes, or to ssh (on my non-standard port), or to attempts to telnet to the (non-standard) HTTP port I'm using. Traceroutes -out- from the VM also get absolutely nowhere... not even one hop. Pings rom the VM to its own (externally routable) IPv4 address work fine. I logged in again via the virtual console and once again, just like the last time this happened (a couple of days ago), I can see nothing obviously wrong. There's plenty of free disk space, and top is showing the CPU as being >95% idle. ifconfig output looks perfectly normal to me... the interface in question is listed as "UP". Whet the devil could be wrong? The relevant hosting company has assured me that they haven't been doing anything new or special lately. The Handbook says that (recent vintage) FreeBSD provides three different flavors of firewalls. Are any of these three enabled by default? What about TCP Wrapper? Is that enabled by default on an out-of-the-box install of 11.1-RELEASE? What else could possibly explain a NIC periodically becoming totally unresponsive... at least from the outside... apparently just because I had the audacity to install and run apache24?