On Thu 24 Aug 2017 at 20:58:18 (-0400), Gene Heskett wrote: > On Thursday 24 August 2017 12:30:37 Dan Ritter wrote: > > On Thu, Aug 24, 2017 at 10:43:56AM -0500, David Wright wrote:
> > > The history of computing is littered with statements like > > > "virtually every computer has exactly one or two NICs". > > > > It used to be zero. > > > > We are currently in the phase of history where this statement is > > true. NICs are both ubiquitous and cheap, yet devices tend to > > come with one (only an ethernet port or only a wifi radio) or > > two (one of each of those, or a wifi radio and a cell radio). > > > > Devices can add more, but they are always special cases: my > > Debian-running firewall has 5 ethernet ports. I occasionally > > add a USB ethernet frob in order to isolate a device that I want > > to talk to directly. Special cases deserve special treatment. > > > > I expect the statement to remain true for the next ten years. > > > > Do you expect differently? If so, why? > > > > > This list is full of postings about the complex DNS system. But > > > how long did /etc/hosts last? Some complexity is unavoidable, > > > but if you try to avoid it, you pay for it later. Look at timezones. > > > Ever allowing computers' internal clocks to run on local time > > > was, with hindsight, a big mistake. Leap seconds might also > > > be seen the same way (still under debate). > > > > /etc/hosts still acts the way it always did -- put in an entry, > > it overrides DNS. > > > That depends entirely on who wrote your /etc/resolv.conf and whether or > not your did a sudo chattr +i /etc/resolv.conf, immediately after > verifying that it works. (and of course that implies it is a real file, > not a softlink to something else. With N-M in the mix and active that > is the only way to keep it from tearing down your network configuration > and leaving you empty files, and no network, if it cannot find a dhcpd > server) (We've heard about your problems concerning /etc/resolv.conf several times now.) I think the file that affects the priority of /etc/hosts is /etc/nsswitch.conf which typically contains a line like: hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 But that misses the point I was making, which requires one to know a fragment of Internet history. /etc/hosts started life as a file containing the address of every host on the network (then ARPANET). Simple, sufficient at the time, but obviously not going to stay the course. Similarly, /dev/sdX just about works well enough for simple, static systems but not for more complex, dynamic ones; eth0 likewise is showing its age for scaling and flexibility, particularly as the newer scheme adds functionality without removing the legacy. Cheers, David.
