/etc/resolv.conf - Number of Nameservers

[John Summerfield]

Ed Greshko wrote:
> Manish Kathuria wrote:
>> What is the maximum number of nameservers mentioned in /etc/resolv.conf
>> which will be queried while looking up a hostname or IP address in Fedora
>> 8 ? Earlier implementations had a ceiling of 3 nameservers which could be
>> queried. Has there been any increase ?
> 
> This is not from fedora...but I suspect it is quite the same....
> 
> Check "man resolv.conf" and you may see the statement "
> 
> "The maximum number of DNS servers to use is set by MAXNS (see 
> <resolv.h> )"
> 
> and if you then look in /usr/include/resolv.h you see....
> 
> # define MAXNS                  3       /* max # name servers we'll 
> track */
> 

More not-working DN servers means longer timeouts on failing lookups.

Once a server responds, even with "dunno" the resolver stops querying DN 
servers and returns "failed." more servers doesn't usually mean more 
reliability; if you can't find one working server in three you need to 
have a good hard look at your list.