topic Re: using numerals as a hostname - not resolving in Operating System - HP-UX

using numerals as a hostname - not resolving

Annelise Wilken — Fri, 09 Dec 2005 11:06:44 GMT

Hello, we have recently migrated a customer from a DG-UX box onto an rx7620 running HP-UX 11:23 only, and the customer is having hostname/IP address resolution issues. Many of the customer's hosts are known as numbers (eg: "0123") , so the hostnames are all numerical, as well as numerical IP addresses. After checking through various HP documentation regarding hostnames it states: “Host names can contain ANY printable character other than a white space, newline, or comment character.” http://docs.hp.com/en/B2355-60103/hosts.4.html, however, since migrating onto HP-UX name resolution is failing – where as it worked ok on DG-UX – my client has changed the hostnames to start with characters followed by numbers and name resolution works! As does adding 1 or more characters as a suffix (eg: "0123x").

So, my client would like an official HP response stating that either: a) purely numeric hostnames can’t be used or b) that they recognise this as a bug and are creating a patch/fix to solve this issue.

Where can I get an offical HP response to this issue? Also, can anyone explain why this is happening?

Many thanks!!

Re: using numerals as a hostname - not resolving

melvyn burnard — Fri, 09 Dec 2005 11:09:52 GMT

For an official HP response, you need to contact your local HP office, or log a call with your HP Response Centre.

Re: using numerals as a hostname - not resolving

Jeff_Traigle — Fri, 09 Dec 2005 11:25:19 GMT

Originally, RFC-952 required host names to begin with a letter. The last character was required to be either a number or a letter. All other characters could be letters, numbers, or hyphens.

RFC-1123 relaxed that requirement so the first character could also be a number.

http://www.rfc-editor.org/rfc/rfc952.txt
http://www.rfc-editor.org/rfc/rfc1123.txt

That's the only references a quick Yahoo! search found for valid host names. Based on that, it seems like HP isn't quite supporting the spec, requiring a letter somewhere in the host name.

Re: using numerals as a hostname - not resolving

Geoff Wild — Fri, 09 Dec 2005 12:00:20 GMT

I'm taking a stab in the dark here - but I believe what is happening is the resolver on HP-UX is based on the bsd resolver...

Which includes RFC1034, RFC1035, RFC1535.

You already have the solution - add a character to the start of the name:

a1234

I don't know if there is a resoler work around...

Place a call with the HP Support Centre...request an enhacement to the resolver routines to allow all numerical hostnames...

Rgds...Geoff

Re: using numerals as a hostname - not resolving

Bill Hassell — Fri, 09 Dec 2005 16:54:55 GMT

Converting a hostname into an IP address is a configurable feature. If you do not use a DNS or NIS server, then the pure number name would only be in /etc/hosts and should be resolvable (but only if there is no /etc/resolv.conf file). If you have a DNS file (/etc/resolv.conf) then hostname resolution is not under control of HP-UX, it is provided by some other computer. So the issue is with the DNS server(s) specified in /etc/resolv.conf. Use nslookup to specifically query each of your DNS servers, something like this:

nslookup "0123" 12.34.56.78

NOTE: the number 0123 is special! A leading zero is interpreted by the shell as an octal flag so 0123 may be translated to an octal value before being sent to nslookup. By enclosing numbers in quotes, the actual string will be sent to the specified DNS server. If you find that numbers do not get resolved at the DNS server (perhaps a Windows based server that is not patched), you can override the order of finding a name using /etc/nsswitch.conf. Change the hosts line from dns then files to files then dns. See the man page for switch.

Re: using numerals as a hostname - not resolving

Annelise Wilken — Thu, 09 Feb 2006 10:23:04 GMT

Customer did not want to pursue this matter further - they have resolved it by not using numerals.