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Dealing with a network knowledge troll!

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  Dealing with a network knowledge troll! Mike Lovell <dev.null@b0h0.com> - 2012-08-23 22:07 -0500
    Re: Dealing with a network knowledge troll! David Brown <david@westcontrol.removethisbit.com> - 2012-08-24 09:05 +0200
    Re: Dealing with a network knowledge troll! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-24 07:17 +0000
      Re: Dealing with a network knowledge troll! Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2012-08-24 10:29 -0500
      Re: Dealing with a network knowledge troll! Mike Lovell <dev.null@b0h0.com> - 2012-08-24 10:53 -0500
        Re: Dealing with a network knowledge troll! "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2012-08-24 14:02 -0400
        Re: Dealing with a network knowledge troll! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-24 20:21 +0000
    Re: Dealing with a network knowledge troll! Richard Kettlewell <rjk@greenend.org.uk> - 2012-08-24 09:07 +0100
    Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-24 12:09 -0500
      Re: Dealing with a network knowledge troll! Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2012-08-24 14:29 -0500
        Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-24 15:58 -0500
          Re: Dealing with a network knowledge troll! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-24 22:23 +0000
            Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-25 12:40 -0500
      Re: Dealing with a network knowledge troll! Richard Kettlewell <rjk@greenend.org.uk> - 2012-08-25 09:38 +0100
        Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-25 12:35 -0500

#1600 — Dealing with a network knowledge troll!

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Hello,

I've got a guy who claims these:

	10.255.255.81/24
	192.168.255.81/24

Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
is reserved for being a broadcast IP.

To which he cites:
http://www.comptechdoc.org/independent/networking/guide/netaddressing.html


Now I immediately know this is wrong because you can use a "0" or "255"
on the end of a host IP:
http://en.wikipedia.org/wiki/IPv4#Addresses_ending_in_0_or_255


And of course the RFC says it's fine to use a "255" in the 1st to 3rd
octets.  Nothing about this is reserved or makes the address
specifically a broadcast one.


And you can even find reachable hosts out there with "255" in them:


host ns2.televork.ee
ns2.televork.ee has address 81.21.255.1

host www.lepton-line.jp
www.lepton-line.jp has address 121.83.255.1


So every router between me and them (for me to reach them) would have to
be broken it allow this, if the other guy is right about them being
invalid!



Question:

Am I correct (the IP's are valid) or is he (the IP's are invalid)?  And why?

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#1601

On 24/08/2012 05:07, Mike Lovell wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Hello,
>
> I've got a guy who claims these:
>
> 	10.255.255.81/24
> 	192.168.255.81/24
>
> Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
> is reserved for being a broadcast IP.
>
> To which he cites:
> http://www.comptechdoc.org/independent/networking/guide/netaddressing.html
>
>
> Now I immediately know this is wrong because you can use a "0" or "255"
> on the end of a host IP:
> http://en.wikipedia.org/wiki/IPv4#Addresses_ending_in_0_or_255
>
>
> And of course the RFC says it's fine to use a "255" in the 1st to 3rd
> octets.  Nothing about this is reserved or makes the address
> specifically a broadcast one.
>
>
> And you can even find reachable hosts out there with "255" in them:
>
>
> host ns2.televork.ee
> ns2.televork.ee has address 81.21.255.1
>
> host www.lepton-line.jp
> www.lepton-line.jp has address 121.83.255.1
>
>
> So every router between me and them (for me to reach them) would have to
> be broken it allow this, if the other guy is right about them being
> invalid!
>
>
>
> Question:
>
> Am I correct (the IP's are valid) or is he (the IP's are invalid)?  And why?
>

You are correct.

The wikipedia article is as good an explanation as any.

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#1602

On Fri, 2012-08-24, Mike Lovell wrote:
>
> Hello,
>
> I've got a guy who claims these:
>
> 	10.255.255.81/24
> 	192.168.255.81/24
>
> Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
> is reserved for being a broadcast IP.
...
> And of course the RFC says it's fine to use a "255" in the 1st to 3rd
> octets.  Nothing about this is reserved or makes the address
> specifically a broadcast one.
...
> Am I correct (the IP's are valid)

If you really have found it stated in the RFCs and the RFCs are not
obsoleted by later ones, of course you are right and don't have to ask
around.

(Why stop at octets 1--3, by the way?  Surely a.b.c.255 can be a valid
unicast address too?)

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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#1604

On 24 Aug 2012, in the Usenet newsgroup comp.os.linux.networking, in article
<slrnk3eajg.ph6.grahn+nntp@frailea.sa.invalid>, Jorgen Grahn wrote:

>Mike Lovell wrote:

>> I've got a guy who claims these:

>>       10.255.255.81/24
>>       192.168.255.81/24

Those are RFC1918 (private) addresses.  Tell the idiot to set up a
couple of boxes in those ranges and try it himself.

>> Are invalid unicast IP's, because any IP with a "255" in it
>> *anywhere* is reserved for being a broadcast IP.

  1122 Requirements for Internet Hosts - Communication Layers. R.
       Braden, Ed.. October 1989. (Format: TXT=295992 bytes) (Updates
       RFC0793) (Updated by RFC1349, RFC4379, RFC5884, RFC6093,
       RFC6298, RFC6633) (Also STD0003) (Status: STANDARD)

RFC1122 section 3.2.1.3 is poorly written, but sub section '(d)' and
'(e)' limit it to the last address in a network/subnet (the -1) only.

>If you really have found it stated in the RFCs and the RFCs are not
>obsoleted by later ones, of course you are right and don't have to
>ask around.

RFC1878

  1878 Variable Length Subnet Table For IPv4. T. Pummill, B. Manning.
       December 1995. (Format: TXT=19414 bytes) (Obsoletes RFC1860)
      (Status: HISTORIC)

>(Why stop at octets 1--3, by the way?  Surely a.b.c.255 can be a
>valid unicast address too?)

Depends on the network mask, but sure.  A facility I worked at for five
years used a 255.255.252.0 (0xff ff fc 00) mask, so three out of four
x.y.z.255 addresses were "normal" host addresses (only a broadcast
where 'z' divided evenly by 4).  Thus,

    198.18.4.0     network address
    198.18.4.1     thru
    198.18.7.254   are host addresses
    198.18.7.255   the ONLY broadcast address of the lot

That meant 198.18.4.255, 198.18.5.255  and 198.18.6.255 were hosts.

        Old guy

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#1605

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On 2012-08-24, Jorgen Grahn <grahn+nntp@snipabacken.se> wrote:
> On Fri, 2012-08-24, Mike Lovell wrote:
>>
>> Hello,
>>
>> I've got a guy who claims these:
>>
>> 	10.255.255.81/24
>> 	192.168.255.81/24
>>
>> Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
>> is reserved for being a broadcast IP.
> ...
>> And of course the RFC says it's fine to use a "255" in the 1st to 3rd
>> octets.  Nothing about this is reserved or makes the address
>> specifically a broadcast one.
> ...
>> Am I correct (the IP's are valid)
>
> If you really have found it stated in the RFCs and the RFCs are not
> obsoleted by later ones, of course you are right and don't have to ask
> around.

The guy rejects the RFC!

	"I also find it amusing that the stupid fuck is arguing with a
	J. Postel RFC that is 21 years old. :)"

Then goes on to say he's worked on IT for 40 years, yata-yata-yata


I thought I would take it to a networking group (not sure which is the
most active network group) and check.

> (Why stop at octets 1--3, by the way?  Surely a.b.c.255 can be a valid
> unicast address too?)

No reason, just I mentioned octet 4 earlier up the post (because of the
WIKI cite).  So that's a given.

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#1607

On Fri, 24 Aug 2012 11:53:11 -0400, Mike Lovell <dev.null@b0h0.com> wrote:


>>> Hello,
>>>
>>> I've got a guy who claims these:
>>>
>>> 	10.255.255.81/24
>>> 	192.168.255.81/24
>>>
>>> Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
>>> is reserved for being a broadcast IP.

Ask him to explain how it's possible then, to access the web site at
http://amoniak.elektron.com.pl

Regards, Dave Hodgins

-- 
Change nomail.afraid.org to ody.ca to reply by email.
(nomail.afraid.org has been set up specifically for
use in usenet. Feel free to use it yourself.)

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#1609

On Fri, 2012-08-24, Mike Lovell wrote:
>
> On 2012-08-24, Jorgen Grahn <grahn+nntp@snipabacken.se> wrote:
>> On Fri, 2012-08-24, Mike Lovell wrote:
>>>
>>> Hello,
>>>
>>> I've got a guy who claims these:
>>>
>>> 	10.255.255.81/24
>>> 	192.168.255.81/24
>>>
>>> Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
>>> is reserved for being a broadcast IP.
>> ...
>>> And of course the RFC says it's fine to use a "255" in the 1st to 3rd
>>> octets.  Nothing about this is reserved or makes the address
>>> specifically a broadcast one.
>> ...
>>> Am I correct (the IP's are valid)
>>
>> If you really have found it stated in the RFCs and the RFCs are not
>> obsoleted by later ones, of course you are right and don't have to ask
>> around.
>
> The guy rejects the RFC!
>
> 	"I also find it amusing that the stupid fuck is arguing with a
> 	J. Postel RFC that is 21 years old. :)"
>
> Then goes on to say he's worked on IT for 40 years, yata-yata-yata

Ok, you don't want to convince yourself he's wrong, but see /him/
backpedal on his claim.  That can be difficult with some people.

> I thought I would take it to a networking group (not sure which is the
> most active network group) and check.
>
>> (Why stop at octets 1--3, by the way?  Surely a.b.c.255 can be a valid
>> unicast address too?)
>
> No reason, just I mentioned octet 4 earlier up the post (because of the
> WIKI cite).  So that's a given.

Ah, yes you did. Sorry.

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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#1603

Mike Lovell <dev.null@b0h0.com> writes:
> Am I correct (the IP's are valid) or is he (the IP's are invalid)?

You are right, he is wrong.

> And why?

In short, because nothing forbids them; it would be bizarre and
arbitrary to do so.

The focus on the dotted-quad notation is an enormous red flag that
someone doesn't know what they're talking about.  It's a notational
convenience for humans, not a technical property.  Interpret IPv4
addresses as binary numbers and it should become clearer just how weird
banning eight-ones strings at particular positions in the middle of them
would be.

-- 
http://www.greenend.org.uk/rjk/

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#1606

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On 8/23/2012 10:07 PM, Mike Lovell wrote:
> Hello,
> 
> I've got a guy who claims these:
> 
> 	10.255.255.81/24
> 	192.168.255.81/24
> 
> Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
> is reserved for being a broadcast IP.
> 
> To which he cites:
> http://www.comptechdoc.org/independent/networking/guide/netaddressing.html
> 
> 
> Now I immediately know this is wrong because you can use a "0" or "255"
> on the end of a host IP:
> http://en.wikipedia.org/wiki/IPv4#Addresses_ending_in_0_or_255
> 
> 
> And of course the RFC says it's fine to use a "255" in the 1st to 3rd
> octets.  Nothing about this is reserved or makes the address
> specifically a broadcast one.
> 
> 
> And you can even find reachable hosts out there with "255" in them:
> 
> 
> host ns2.televork.ee
> ns2.televork.ee has address 81.21.255.1
> 
> host www.lepton-line.jp
> www.lepton-line.jp has address 121.83.255.1
> 
> 
> So every router between me and them (for me to reach them) would have to
> be broken it allow this, if the other guy is right about them being
> invalid!
> 
> 
> 
> Question:
> 
> Am I correct (the IP's are valid) or is he (the IP's are invalid)?  And why?
> 
> 

Well, it may say its valid for use and all, and a lot depends on the
mask used.  But, it would be an odd thing to do as most avoid this
value.  Using it may find some bugs scattered around in software.
Arguing about specs like this is a bit silly, anyway.  Its IPv6 time,
lots of room for adventure especially concerning the conversion from
IPv4.  Should have some dazzling times ahead.

PS:  Anyone seeing a "255" would think its some kind of broadcast
thingy, except us.
- -- 
Steal a little and go to jail, steal a lot and become King.
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#1608

On Fri, 24 Aug 2012, in the Usenet newsgroup comp.os.linux.networking,
in article <k18chb$9dp$1@dont-email.me>, telsar wrote:

>Well, it may say its valid for use and all, and a lot depends on the
>mask used.  But, it would be an odd thing to do as most avoid this
>value.  Using it may find some bugs scattered around in software.

About a week ago, of the 118784 networks allocated or assigned by the
five Regional Internet Registries, 600 had a '255' in the second or
third octet.  5 of those 600 (128.255.0.0 being UofIowa, 170.255.0.0.
192.12.255.0, 192.51.255.0 and 192.66.255.0) were assigned in the late
1980s.  I think someone might have noticed by now.

>Its IPv6 time, lots of room for adventure especially concerning the
>conversion from IPv4.

About a week ago, there were 11619 IPv6 networks - and for perspective
there were 11675 IPv4 networks at the end of 1991.

>PS:  Anyone seeing a "255" would think its some kind of broadcast
>thingy, except us.

Nearly all computer users wouldn't even recognize an IP address of
either version 4 _or_ 6.

        Old guy

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#1610

On 8/24/2012 2:29 PM, Moe Trin wrote:
> On Fri, 24 Aug 2012, in the Usenet newsgroup comp.os.linux.networking,
> in article <k18chb$9dp$1@dont-email.me>, telsar wrote:
> 
>> Well, it may say its valid for use and all, and a lot depends on the
>> mask used.  But, it would be an odd thing to do as most avoid this
>> value.  Using it may find some bugs scattered around in software.

I stand by this.  The world is full of half baked network software
especially in older gear and code.

> 
> About a week ago, of the 118784 networks allocated or assigned by the
> five Regional Internet Registries, 600 had a '255' in the second or
> third octet.  5 of those 600 (128.255.0.0 being UofIowa, 170.255.0.0.
> 192.12.255.0, 192.51.255.0 and 192.66.255.0) were assigned in the late
> 1980s.  I think someone might have noticed by now.

I did not say it wasn't true.  IPv4 addresses were always scarce.

> 
>> Its IPv6 time, lots of room for adventure especially concerning the
>> conversion from IPv4.
> 
> About a week ago, there were 11619 IPv6 networks - and for perspective
> there were 11675 IPv4 networks at the end of 1991.

I can hardly wait until IPv4 is eradicated and the world can be
comprised of static addresses as "the goddess" had intended.

> 
>> PS:  Anyone seeing a "255" would think its some kind of broadcast
>> thingy, except us.
> 
> Nearly all computer users wouldn't even recognize an IP address of
> either version 4 _or_ 6.

That is for sure.  Most network folks in industry deal in the reserved
ones anyway. 10.0.0.0 and 192.168.0.0

The real addresses are in the world of the ISPs and folks running real
stuff on the Internet.  Far fewer of these folks.

> 
>         Old guy
> 


-- 
Steal a little and go to jail, steal a lot and become King.

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#1611

On Fri, 2012-08-24, telsar wrote:
> On 8/24/2012 2:29 PM, Moe Trin wrote:
>> On Fri, 24 Aug 2012, in the Usenet newsgroup comp.os.linux.networking,
>> in article <k18chb$9dp$1@dont-email.me>, telsar wrote:
>> 
>>> Well, it may say its valid for use and all, and a lot depends on the
>>> mask used.  But, it would be an odd thing to do as most avoid this
>>> value.  Using it may find some bugs scattered around in software.

You snipped the part by Moe Trin you responded to:

    About a week ago, of the 118784 networks allocated or assigned by
    the five Regional Internet Registries, 600 had a '255' in the
    second or third octet.  5 of those 600 (128.255.0.0 being UofIowa,
    170.255.0.0. 192.12.255.0, 192.51.255.0 and 192.66.255.0) were
    assigned in the late 1980s.  I think someone might have noticed by
    now.

> I stand by this.  The world is full of half baked network software
> especially in older gear and code.

I assume you what you stand by is your statement "most avoid this
value". Citation needed, please. As he writes, 255 in addresses is
legal, /and/ widely used.

> I can hardly wait until IPv4 is eradicated and the world can be
> comprised of static addresses as "the goddess" had intended.

/That/ I can agree with.

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

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#1620

On 8/24/2012 5:23 PM, Jorgen Grahn wrote:

I give up.  Its not even possible to agree with you and point at why
someone would be mistaken due to common practices.

It doesn't matter anyway.


-- 
Steal a little and go to jail, steal a lot and become King.

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#1617

telsar <noone@nowhere.com> writes:
> Well, it may say its valid for use and all, and a lot depends on the
> mask used.  But, it would be an odd thing to do as most avoid this
> value.  Using it may find some bugs scattered around in software.

Did you have any specific software in mind, or are you just making this
up?

-- 
http://www.greenend.org.uk/rjk/

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#1619

On 8/25/2012 3:38 AM, Richard Kettlewell wrote:
> telsar <noone@nowhere.com> writes:
>> Well, it may say its valid for use and all, and a lot depends on the
>> mask used.  But, it would be an odd thing to do as most avoid this
>> value.  Using it may find some bugs scattered around in software.
> 
> Did you have any specific software in mind, or are you just making this
> up?
> 

I am making it up.  Its been like 15 or more years since I had a piece
of network gear wig out over this.  Seems like it was a Livingston
portmaster.  And another was a pre-release of the Total Control Hub from
3com they were hoping we would use.  I found that little jewel, and
also, an issue with their frame relay implementation.

Doesn't really matter anyway, if you have no respect for others opinions.

-- 
Steal a little and go to jail, steal a lot and become King.

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