[WEB4LIB] Re: Linking to numeric IP addresses vs. alpha in URLS

James Klock j-klock at evanston.lib.il.us
Mon Feb 1 16:47:19 EST 1999

Understand that manipulating your hosts files is essentially similar to
using HTTP links which reference IP numbers: in both cases, you presume to
know the IP number you want.  The only distinction is that if you use the
HOSTS file, you'll have to update that file on every workstation every time
you discover a new IP # that you need to include.

So if you don't recommend HTTP links which directly call IP numbers (on
grounds that those IP numbers will change too often to keep up with), then
you probably shouldn't recommend resolving your hostnames within a local
hosts file (on grounds that those IP numbers will change too often, and
with a potentially MORE cumbersome proceedure to keep up each time they do!)

Example:  you normally point to HREF=http://www.example.com/, which as of
today resolves as .  So you create a sample hosts file which
includes an entry to resolve any calls to www.example.com as ,
and you distribute this hosts file to every workstation you want to see the
service.  Tomorrow, the vendor in question moves their web-based service to .  You now must re-edit your host file, AND REDISTRIBUTE IT!

The next day, the vendor brings a new search-engine server online, so that
some of their HTML codebase points to http://search.example.com/ (which
resides at  Now, you not only need to track down why you
aren't able to successfully complete some of your searches (and find the
URL that you aren't resolving), but you also need to edit your host file,
and redistribute it.

This is not the right answer.  Even if your vendors are fairly static and
don't make references within their pages to their own site based on
hostname (this is a BIG set of ifs), you're probably better off with IP
numbers written straight into your HTML.  

As has been eloquently stated by JQ Johnson, the right answer is to get
your service providers to, ahem, provide services.  If they can't or won't
do that, perhaps you can stop paying them and find someone who will meet
your needs.

It's also notable that some implementations of DNS clients will not send
requests to a secondary DNS if the primary responds (even if it responds
with "no known host").  So simply adding a secondary DNS may not be
helpful.  Turning your primary DNS into a caching server, on the other
hand, might...


>   Bob Jones has a good suggestion with the Hosts file.  Also, going ahead
>with ip's as links is not a good resolution if you have vendors like some
>of mine that change servers daily, you will have to edit links daily or
>worse.  Normally vendors will use up to three different servers from what
>I've seen so, if you use a secondary DNS server or a Hosts file you could
>probably find out the three or so ips they use in short order.  Then just
>add them  to your Hosts file or a second DNS server.  

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