Date: Wed, 23 Jul 1997 12:05:04 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: francis@mail.adc.iii.org.tw (Francis W.S. Yeh) Cc: stable@FreeBSD.ORG Subject: Re: Bug report Message-ID: <199707230235.MAA04966@genesis.atrad.adelaide.edu.au> In-Reply-To: <33D55B3D.1C4B9ADF@adc.iii.org.tw> from "Francis W.S. Yeh" at "Jul 23, 97 09:15:41 am"
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Francis W.S. Yeh stands accused of saying:
> Dear Sir:
> Here is a situation I met on our FreeBSD 2.2.2R (prior to
> 2.2-970625-RELENG) that I consider a bug. A transcript of the commands
> that shows this problem is listed below:
> -------------------------------------------------------------------
> mail2[francis]:~> nslookup www.bcc.com.tw
> Server: mail.adc.iii.org.tw
> Address: 140.92.75.200
>
> Non-authoritative answer:
> Name: BCC_WWW.BCC.COM.TW
> Address: 203.69.33.1
> Aliases: www.bcc.com.tw
>
> mail2[francis]:~> ping www.bcc.com.tw
> ping: unknown host www.bcc.com.tw
> mail2[francis]:~>
> -------------------------------------------------------------------
>
> On another FreeBSD 2.2.2R system in the same IP subnet which serves
> as our name server, the same problem exists. However, on two other
> systems in the same IP subnet with the same DNS settings, the situation
> does not occur. One of them is a Sun Ultra1 running Solaris 2.5.1. The
> other one is a Windows NT workstation 4.0 Chinese edition Pentium PC.
> I posted the problem on a news group for FreeBSD which is local to
> our country a few days ago and got some response. Another one with a
> FreeBSD 2.2.2R, a FreeBSD 2.2-970625-RELENG and an older FreeBSD system
> responded with similar observation. He found the same problem on his
> FreeBSD 2.2.2R and 2.2-970625-RELENG systems but the older system works
> well.
There have been changes in the DNS software ("bind") between the older
systems and FreeBSD 2.2.2.
> Some one suggests that the problem is related to the other FQDN of
> www.bcc.com.tw, i.e. BCC_WWW.BCC.COM.TW, for it has a '_' in its host
> name. According to RFC1034, '_' is not said to be an allowable label
> character. However, I still wonder why this happens:
This is correct, and this is why ping fails.
> (1) Why does nslookup works while ping fails?
nslookup is returning the database record. Ping is attempting to
obtain an address, but the record specifies an illegal hostname and
> (2) Why does other systems works (including older version of FreeBSD)
> while FreeBSD 2.2.2R and later fails?
Because the older systems predate the rigid enforcement of the legal
character set for hostnames.
Incidentally, you should upgrade the DNS software all of the systems
which are not enforcing these rules, as they contain security holes
which can be exploited by hostile parties to gain root access to your
systems.
--
]] Mike Smith, Software Engineer msmith@gsoft.com.au [[
]] Genesis Software genesis@gsoft.com.au [[
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