Return-Path: Received: from extranet.sessys.com ([50.116.54.220]:34329 "EHLO extranet.sessys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752984AbbFIB5k convert rfc822-to-8bit (ORCPT ); Mon, 8 Jun 2015 21:57:40 -0400 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: [PATCH] rpc.nfsd: add no-ipv4 and no-ipv6 options From: Sean Elble In-Reply-To: <20150608211210.GC27887@fieldses.org> Date: Mon, 8 Jun 2015 21:57:33 -0400 Cc: Chuck Lever , Kinglong Mee , Linux NFS Mailing List , linux-nfs-owner@vger.kernel.org Message-Id: <62BB9BD0-7234-41FD-A857-E2ACF7443310@sessys.com> References: <55743EDE.7070707@gmail.com> <3CE6594A-508B-4BBD-9E52-CF9EDDA6274D@oracle.com> <557597D3.8090401@gmail.com> <312511264c19c5a98cbd1062531b306e@mail.sessys.com> <2F03891D-9240-4A8E-BEEB-7F5BBAD1B5FE@gmail.com> <76DB6DF0-8409-4D42-B2FD-6C7B08B148A5@gmail.com> <20150608211210.GC27887@fieldses.org> To: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Jun 8, 2015, at 5:12 PM, J. Bruce Fields wrote: > > On Mon, Jun 08, 2015 at 10:33:22AM -0400, Sean Elble wrote: >> On 08.06.2015 10:27, Chuck Lever wrote: >>>> I don’t understand the need to “turn off” an address family. >>>> That’s what >>>> /etc/netconfig is supposed to be for. What’s not happening here that >>>> should be? >>> >>> What I mean is: I’d rather not add more command line options if there >>> is a way for rpc.nfsd to automatically and quietly do what is needed. >>> But I don’t understand the use case here. Sean, can you explain it >>> for >>> bears of little brain? >> >> Sure, and please correct me if any of my understanding is incorrect >> (as it may well be). In my environment, I wanted to have NFS only >> listen on one interface of a multihomed host. In using the "--host" >> parameter to do so, I saw the error message regarding IPv6 thrown. >> While disabling IPv6 globally in /etc/netconfig is an option (one I >> understand to be "global", in that it'd affect *all* applications on >> the host), it'd be nice to disable IPv6 for a single service/daemon >> instead. > > But doesn't something like > > rpc.nfsd --host 10.0.0.1 --no-ipv6 > > seem a bit redundant? In that case, perhaps it does. But what if you were to use a hostname that resolved to both IPv4 and IPv6 addresses? > > I mean, you've already told it to listen to that one (ipv4) address. > That'd argue for just disabling the warning in this case, I think. But > my understanding of IPv6 is still poor. Yours and mine both. But until it gets better, I’m very comfortable in just turning it off in places where 1) I know it’s not needed and 2) Places where exploits could linger with most of our emphasis on IPv4 still. > > --b. >