Re: Bug in gethostbyaddr() on some systems
Lawrence MacIntyre - 615.576.0824 (lpz@nautique.epm.ornl.gov)
Thu, 2 Mar 1995 10:08:44 -0500 (EST)
On Wed, 1 Mar 1995, Jon Peatfield wrote:
> Both DECs (OSF/1 1.3, 2.0, 3.0) and HPs (if you apply certain libc patches
> (e.g. PHCO_5153 etc) to get nsswitch.conf stuff) have a bug in gethostbyaddr()
> if you have set the search order in nsswitch.conf/svc.conf to
> files,dns/local,bind. That is if you have set the resolver code to look in
> the /etc/hosts file first and then go on to look in the DNS for results.
> Other orders may also have bugs I've not investigated this.
>
> The bug causes the h_aliases field of the hostent struct to get filled in with
> stuff from the last valid line in your /etc/hosts rather than whatever it
> should get.
>
> Fortunately there is a simple fix -- just add a dummy line with no aliases to
> the end of your /etc/hosts file, the following appears to work for me:
>
> # Dummy entry to work round bug in gethostbyaddr() on HP/DEC
> 127.0.0.1 GARBAGENAME
I tested this on OSF/1 v2.0 and v3.0. My machines did something a bit
different. The h_aliases pointer pointed into the middle of the h_name
data. There was no sign of any aliases from /etc/hosts. However,
putting a bogus line as the last line in the host file did fix the problem.
Lawrence
~
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lpz@nautique.epm.ornl.gov Lawrence MacIntyre
lpz@ornl.gov Oak Ridge National Laboratory 615.574.8696