Re: Bug in gethostbyaddr() on some systems

[lpz () nautique epm ornl gov (Lawrence MacIntyre - 615.576.0824)]

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