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[leafnode-list] Re: Disabling The "Is Valid FQDN" Check

On 2 May 2011, at 23:05, Whiskers wrote:
> On Mon, 2 May 2011 15:37:56 +0100 Sabahattin Gucukoglu
> <mail@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>> I can see that the fQDN validation is well-intended, but in my case it's
>> unwelcome because: 1.  I use zeroconf networking, that puts my machine
>> in the ".local" domain, and makes changing it globally unwanted and
>> difficult. 
> It's so long since I last installed Leafnode (my present installation has 
> been running for at least 4 years) that I can't remember; does Leafnode 
> refuse to run if the "hostname" of the machine isn't an FQDN?  I'm quite 
> sure it doesn't require the machine to have a name that can be found on a 
> public DNS server - mine certainly can't!

Yeah, it goes out of its way, refusing to let you use many common "Local" designations, including .local, .localdomain, .test, .example (and all the example.* domains).  There's an entire source file devoted to this one little check, in fact.  But yes, DNS validation isn't done on the name, it only uses gethostname to find your hostname, then gethostbyname to get the addresses, then look up the aliases on those addresses to find the FQDN; it should work if you just edit /etc/hosts.  Or you can just do what I did and set it directly in config (although it still makes a fuss and changes its opening banner accordingly).

> Man leafnode includes this:
>    hostname = host.domain.country
>        If your messages do not already have message IDs  (generated  by
>        the  newsreader),  Leafnode will generate a message ID for them.
>        However, it will never ever overwrite an existing message ID. By
>        default,  it  tries  to  do this from the name of your computer.
>        However, some upstream servers demand message IDs of  a  certain
>        type.  In  this case, you can override the name of your computer
>        by setting "hostname" to a sensible value.  The  abuse  of  this
>        option  can cause your upstreams to silently drop your postings!
> Surely it isn't difficult to put something in there that works?  The 
> address of your upstream news-server shouldn't be objected to by anyone.

Those are used by my upstream, but I don't see why it shouldn't work, indeed.  Anyway, since I've been using my machine's DNS would-be name and nothing bad has happened, there's no need to change now.

> 2.  Anyway, my upstream server rewrites my message-ids,
>> making the need to pick a name, pointless.  
> Ghastly!  Change to a news-server that behaves better.  Having MIDs that 
> can be identified as yours, is an important part of your usenet identity.

I agree, but it's impossible.  Private news server.  I also suspect, now I've had Leafnode running for a while, that at least one of my newsreaders (Unison) isn't even *generating* Message-IDs itself.  So I'll have a look at the articles fetched through Leafnode once I begin posting through it.

> And, 3.  I do not like the
>> idea of using a name - any name - not under my control, whether it
>> exists in DNS or not.  MSGids must be globally unique, not valid; this
>> is the new reality.  It is exactly the same thinking that makes any
>> valid domain or domain name portion in munging a very bad idea.
> I agree that the usenet and NNTP systems don't seem to break when MIDs have
> nonsense to the right of the @ character.
> An FQDN doesn't have to be listed on any DNS server; it doesn't even have 
> to be unique to one machine.  I think something like mycomputer.local is a 
> perfectly valid FQDN; it's certainly fine for a "hostname", as far as I 
> know.

This doesn't seem to be the thinking of Leafnode's authors.  The current standards derive from mail, which makes the RHS of a Message-Id a SHOULD domain.  The emphasis is stronger in netnews because there are relatively more globally unique Message-IDs floating around out there, but it's still a SHOULD, for good reasons.  Some people simply don't have access to a domain or domain-like quantity that is not assuredly theirs.  I especially appreciate the way news.individual.net has handled this, setting aside mid.individual.net just for this use, and putting an entry in DNS with a TXT to make it valid, semantically and actually, as an FQDN.

> Please can we have a feature in future leafnode releases that, while
>> defaulting to on, makes it entirely possible to disable at runtime.
>> Just like we have with the allowStrangers option.  For now I am using my
>> machine name in my own registered domain using the leafnode-only config
>> option "hostname", but would sooner not assume an identity that isn't
>> real, in DNS.
> You have a registered domain name of your own and you're using it properly, 
> as far as I can see.  Why do you object to that?

The machine isn't directly related to the domain, except in the tenuous since that I own both.  I agree, it's nebulous, but I think the check is an imposition and not a help.

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