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On 03/08/2013 03:32 AM, Alan McKinnon wrote: |
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> On 08/03/2013 02:29, Michael Mol wrote: |
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>> On 03/07/2013 05:24 PM, Alan McKinnon wrote: |
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>>> Anyone know if there's a way to get /etc/hosts to support the notion of |
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>>> an include file? I did my homework and found nothing, maybe someone else |
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>>> knows more. |
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>>> |
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>>> I really do need this, I have an app that discovers things on the |
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>>> network and knows their address. This makes it's automated way into DNS |
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>>> but takes a few days, and another app needs to use the fqdn right now. |
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>>> So /etc/hosts is the way to go for the interim three days. |
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>>> |
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>>> I've worked around it by creating /etc/hosts.d/ containing a header and |
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>>> a data file. cat the two and redirect to /etc/hosts.d/hosts and the real |
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>>> hosts file is a symlink to that. It's a sub-directory as none of these |
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>>> apps run as root and only root can modiy the real hosts file. |
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>>> |
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>>> This works well enough, but a supported include mechanism would make |
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>>> life so much simpler, not to mention easier for my colleagues to |
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>>> understand what the blazes I set up :-) |
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>> |
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>> No, there's not an "include" directive. |
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>> |
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>> There are, however, two other ways to get hostnames recognized. |
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>> |
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>> The first is /etc/resolv.conf . You can point your host at a local DNS |
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>> server which is aware of the discovered hosts, and which forwards the |
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>> rest of the queries. (This is how Samba 4's internal DNS server |
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>> operates; anything it knows, it responds to. Everything else, it forwards.) |
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>> |
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>> Read the manpage for resolv.conf...there's a lot of stuff in there |
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>> you'll want to know as you start coping with IPv6. (And some useful |
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>> stuff if you want to favor a particular IP range...) |
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> |
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> And the day started off so well. Then you had to come along and mention |
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> IPv6.... :-) |
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> |
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> IPv6 is wonderfully easy to use client-side and reasonably easy to plug |
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> into an existing network (the routers mostly know what to do already). |
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> The fun starts when you need to write an app that tracks and does range |
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> allocations at ISP scale, all while keeping the PTRs in line too. Sadly |
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> for me, my team works in that area and such a magic app is one of our |
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> deliverables |
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|
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My mouth is watering... |
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|
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> |
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> One day when I've climbed down off the walls and my fingernails have |
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> grown back, I might be up to relating what it is taking to get that |
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> done.... :-) |
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|
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I don't suppose you knew I'm a huge IPv6 advocate, and travel around my |
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state giving free training sessions... |
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|
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I would absolutely love to hear about the problems you're facing. |
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Further, I'd love to help you get past them...and can put you in touch |
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with experts who might also be able to help. |
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|
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|
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> |
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>> |
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>> The second is /etc/nsswitch.conf . nsswitch.conf is how you inject |
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>> samba-discovered, NIS-offered -- or whatever provider you care to inject |
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>> -- hostname databases into the system resolver. You could have it query |
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>> your provided database first, moving on to other sources if your |
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>> provided database doesn't have what you're looking for. (I'm actually |
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>> kinda surprised avahi doesn't come with an nss plugin...) |
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> |
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> One day I should read nsswitch's man page completely. I never needed to |
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> know more than "dns files" for the hosts directives and that shadow does |
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> user. All those other lookup schemes are things I never use. |
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|
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I've never mucked with NIS, but I muck with samba from time to time. |
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|
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If you're already in a developer context, I'd suggest writing an NSS |
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plugin the system resolver can check on. That's the angle I'd take in |
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your circumstance. |