BIND 'max-cache-size' Value on FreeBSD-13.0

[Michael Sinatra]

On 9/2/21 2:59 PM, Mark Tinka wrote:
> 
> 
> On 9/2/21 23:51, Michael Sinatra wrote:
> 
>>
>> I have noticed this also and have opened a (similar but different) 
>> issue, but it's a bit weird how it manifests itself.
>>
>> On your freebsd installation, make sure that all of your interfaces 
>> are configured and that bind can listen on them.  (They don't 
>> necessarily need to be up; they just need to be configured.)
>>
>> Also, 'listen-on[-v6] any;' is more likely to prevent this kind of 
>> memory leaking than having it listen on explicit addresses.  But the 
>> way I can (more) reliably reproduce it is to have a 'listen-on' 
>> statement that references a non-existent interface/address.
>>
>> I think this is a libuv problem, but I have been really short on time 
>> to troubleshoot.  But in the meantime, I would check on your 
>> 'listen-on' statements and make sure there aren't any stray addresses 
>> in there.
> 
> What we have on all of our name servers is the below:
> 
> // If named is being used only as a local resolver, this is a safe default.
> // For named to be accessible to the network, comment this option, specify
> // the proper IP address, or delete this option.
> //      listen-on       { 127.0.0.1; };
> 
> // If you have IPv6 enabled on this system, uncomment this option for
> // use as a local resolver.  To give access to the network, specify
> // an IPv6 address, or the keyword "any".
>          listen-on-v6    { ::1; };

It *feels* like the above ^^ could be the culprit.  'listen-on any' 
ought to listen on the loopback interface in addition to all other 
configured ethernets and loopbacks.  OTOH, the libuv-based versions of 
BIND (e.g. >=9.16.x) appear to get kind of weird/confused with certain 
types of listen-on statements.

>          listen-on-v6    { any; };
> 
> We are running dual-stack on all name servers, and both IPv4 and IPv6 
> reachability is confirmed solid.
> 
> On IPv4, we are listening on just the main interface. On IPv6, we are 
> listening on both the localhost and the main interface. Not sure if this 
> matters.
> 
> For local resolution on each name server, it refers to localhost for 
> both IPv4 and IPv6 in '/etc/resolv.conf'. Given our configuration, it's 
> using ::1 for local resolution, whenever that may be required, since 
> 127.0.0.1 has nothing listening on it. Thanks.

'listen-on any;' is the default for v4, so you should actually be 
listening on 127.0.0.1 in addition to everything else (since all of your 
listen-on's for v4 appear to be commented out).  You *should* be able to 
remove 'listen-on-v6    { ::1; };' and just leave the 'listen-on-v6    { 
any; };' in place.  Doing a 'sockstat | grep named' on FreeBSD should 
confirm this once you restart named (pretty sure you already knew that, 
but I thought I'd mention it for completeness).

michael