Hi.
Is there any way to prevent the gethostbyname() function not to read the nscd cache on Linux?
Thanks in advance!
+1
A:
don't use nscd? :)
Seriously, if you're relying on gethostbyname() you may want to use libresolv and call res_gethostbyname() instead.
Although that is considered a security flaw by djb at least :)
Consider using the djbdns client library. Very secure, fast, and solid.
John Weldon
2009-06-11 22:49:06
Thanks for the tip, but it looks somewhat old (2001)?Also, any idea if it header-level library, or the libraries can be static-linked?
SyBer
2009-06-12 12:05:53
Yes it's old, but very solid. I don't know about header level / static linking though, but the source is in the public domain so you could experiment with it.
John Weldon
2009-06-12 12:27:15
And, it's no older than gethostbyname() :)
John Weldon
2009-06-12 12:27:54
Check out http://www.fefe.de/djb/ - you're looking for dns.a. Static linking is how djb rolls.
Mark Johnson
2010-02-10 22:59:39
+2
A:
Not really an answer, but use getaddrinfo(3) instead :)
As far as nscd is concerned, here's from the nscd.conf(5) manual page:
enable-cache service <yes|no>
Enables or disables the specified service cache.
You'll have to find out what the correct service for DNS is.
Nikolai N Fetissov
2009-06-11 23:47:17
Thanks for the getaddrinfo() - it looks as it not being cached by nscd indeed (at least in man page)?I prefer not to disable the cache at all, as it's only required for particular app.
SyBer
2009-06-12 12:01:56
Hi.Can someone provide an example how to use getaddrinfo() to get the IP address?Thanks.
SyBer
2009-06-13 00:15:47
Managed to get getaddrinfo() running from here:http://cboard.cprogramming.com/windows-programming/16888-resolving-hostname-using-getaddrinfo-winsock.html
SyBer
2009-06-13 23:50:43
A:
I don't think gethostbyname really caches entries. It's most likely your dns-cache itself.
Suvesh Pratapa
2009-06-12 01:03:56
Actually it uses nscd cache. The problem with this caused when the IP changes - it take A LOT (10 min by default) time the nscd refresh the cache and try to resolve it again.
SyBer
2009-06-12 11:58:55