Public DNS - recursion no - Access to the Internet

Pascal Hambourg pascal.mail at
Mon Feb 19 23:02:39 UTC 2007

Jarek Buczynski a écrit :
> Below is next quote:
> "If you use multiple nameserver directives, don't use the loopback address!
> There's a bug in some Berkeley-derived TCP/IP implementations that can cause
> problems with BIND if the local nameserver is down. The resolver's connected
> datagram socket won't rebind to a new local address if the local nameserver
> isn't running, and consequently the resolver sends query packets to the
> fallback remote nameservers with a source address of When the
> remote nameservers try to reply, they end up sending the reply packets to
> themselves."

Wow, that's a bug !
However, the sender's IP stack should refuse to send the packet out on 
the network because adresses within are invalid outside a 
host. And even though, the receiver's IP stack should also drop the 
incoming packet for the same reason. So, in order for the remote 
nameserver to send a reply, we need a lot of broken software.

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