In message <BANLkTinAZvLc4oQEW5Nq8eTrch=x6hs...@mail.gmail.com>, Jeremy writes: > > "DK" may not be hierarchical, but "DK." is. If you try to resolve "DK" on
"DK." is NOT a hostname (RFC 952). It is NOT legal in a SMTP transaction. It is NOT legal in a HTTP header. > it's own, many (most? all?) DNS clients will attach the search string/domain > name of the local system in order to make it a FQDN. The same happens when > you try and resolve a non-existent domain. Such as > alskdiufwfeiuwdr3948dx.com, in wireshark I see the initial request followed > by alskdiufwfeiuwdr3948dx.com.gateway.2wire.net. However if I qualify it > with the trailing dot, it stops after the first lookup. DK. is a valid FQDN > and should be considered hierarchical due to the dot being the root and > anything before that is a branch off of the root. see RFC1034 You need to write 1000 lines of: RFC 1034 DOES NOT CHANGE WHAT IS A LEGAL HOSTNAME Go READ RFC 1034. "DK." it is NOT a valid heirachical hostname. Just because some random piece of software lets you get away with it does not make it a legal nor does it make it a good idea. Mark > -Jeremy > > On Sun, Jun 19, 2011 at 7:08 PM, Mark Andrews <ma...@isc.org> wrote: > > > > > In message <g339j59ywz....@nsa.vix.com>, Paul Vixie writes: > > > Adam Atkinson <gh...@mistral.co.uk> writes: > > > > > > > It was a very long time ago, but I seem to recall being shown > > http://dk, > > > > the home page of Denmark, some time in the mid 90s. > > > > > > > > Must I be recalling incorrectly? > > > > > > no you need not must be. it would work as long as no dk.this or dk.that > > > would be found first in a search list containing 'this' and 'that', where > > > the default search list is normally the parent domain name of your own > > > hostname (so for me on six.vix.com the search list would be vix.com and > > > so as long as dk.vix.com did not exist then http://dk/ would reach > > "dk.") > > > -- > > > Paul Vixie > > > KI6YSY > > > > DK should NOT be doing this. DK is *not* a hierarchical host name > > and the address record should not exist, RFC 897. The Internet > > stopped using simple host names in the early '80s. In addition to > > that it is a security issue similar to that described in RFC 1535. > > > > Mark > > -- > > Mark Andrews, ISC > > 1 Seymour St., Dundas Valley, NSW 2117, Australia > > PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org > > > > > > --bcaec51f900961620b04a619d97b > Content-Type: text/html; charset=ISO-8859-1 > Content-Transfer-Encoding: quoted-printable > > "DK" may not be hierarchical, but "DK." is. If you try = > to resolve "DK" on it's own, many (most? all?) DNS clients wi= > ll attach the search string/domain name of the local system in order to mak= > e it a FQDN. The same happens when you try and resolve a non-existent domai= > n. Such as <a href=3D"http://alskdiufwfeiuwdr3948dx.com">alskdiufwfeiuwdr39= > 48dx.com</a>, in wireshark I see the initial request followed by =A0<meta h= > ttp-equiv=3D"content-type" content=3D"text/html; charset=3Dutf-8"><a href= > =3D"http://alskdiufwfeiuwdr3948dx.com.gateway.2wire.net">alskdiufwfeiuwdr39= > 48dx.com.gateway.2wire.net</a>. However if I qualify it with the trailing d= > ot, it stops after the first lookup. DK. is a valid FQDN and should be cons= > idered hierarchical due to the dot being the root and anything before that = > is a branch off of the root. see RFC1034<div> > <br></div><div>-Jeremy<br><br><div class=3D"gmail_quote">On Sun, Jun 19, 20= > 11 at 7:08 PM, Mark Andrews <span dir=3D"ltr"><<a href=3D"mailto:marka@i= > sc.org">ma...@isc.org</a>></span> wrote:<br><blockquote class=3D"gmail_q= > uote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1e= > x;"> > <div><div></div><div class=3D"h5"><br> > In message <<a href=3D"mailto:g339j59ywz....@nsa.vix.com">g339j59ywz.fsf= > @nsa.vix.com</a>>, Paul Vixie writes:<br> > > Adam Atkinson <<a href=3D"mailto:gh...@mistral.co.uk">ghira@mistral= > .co.uk</a>> writes:<br> > ><br> > > > It was a very long time ago, but I seem to recall being shown <a = > href=3D"http://dk" target=3D"_blank">http://dk</a>,<br> > > > the home page of Denmark, some time in the mid 90s.<br> > > ><br> > > > Must I be recalling incorrectly?<br> > ><br> > > no you need not must be. =A0it would work as long as no dk.this or dk.= > that<br> > > would be found first in a search list containing 'this' and &#= > 39;that', where<br> > > the default search list is normally the parent domain name of your own= > <br> > > hostname (so for me on <a href=3D"http://six.vix.com" target=3D"_blank= > ">six.vix.com</a> the search list would be <a href=3D"http://vix.com" targe= > t=3D"_blank">vix.com</a> and<br> > > so as long as <a href=3D"http://dk.vix.com" target=3D"_blank">dk.vix.c= > om</a> did not exist then <a href=3D"http://dk/" target=3D"_blank">http://d= > k/</a> would reach "dk.")<br> > > --<br> > > Paul Vixie<br> > > KI6YSY<br> > <br> > </div></div>DK should NOT be doing this. =A0DK is *not* a hierarchical host= > name<br> > and the address record should not exist, RFC 897. =A0The Internet<br> > stopped using simple host names in the early '80s. =A0In addition to<br= > > > that it is a security issue similar to that described in RFC 1535.<br> > <br> > Mark<br> > <font color=3D"#888888">--<br> > Mark Andrews, ISC<br> > 1 Seymour St., Dundas Valley, NSW 2117, Australia<br> > PHONE: <a href=3D"tel:%2B61%202%209871%204742" value=3D"+61298714742">+61 2= > 9871 4742</a> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 INTERNET: <a href=3D"mailto:= > ma...@isc.org">ma...@isc.org</a><br> > <br> > </font></blockquote></div><br></div> > > --bcaec51f900961620b04a619d97b-- -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org