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I am running a oracle linux server as an operational box. I've noticed random lockups on VNC, SSH, and web server request. I looked at my message log and see alot of random resolving.

[user@SERVER1 etc]# tail /var/log/messages
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '255.11.168.192.in-addr.arpa/PTR/IN': 2001:500:2f::f#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '255.11.168.192.in-addr.arpa/PTR/IN': 2001:7fe::53#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '255.11.168.192.in-addr.arpa/PTR/IN': 2001:dc3::35#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '255.11.168.192.in-addr.arpa/PTR/IN': 2001:500:1::803f:235#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '255.11.168.192.in-addr.arpa/PTR/IN': 2001:7fd::1#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '108.10.168.192.in-addr.arpa/PTR/IN': 2001:500:2f::f#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '108.10.168.192.in-addr.arpa/PTR/IN': 2001:7fe::53#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '108.10.168.192.in-addr.arpa/PTR/IN': 2001:dc3::35#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '108.10.168.192.in-addr.arpa/PTR/IN': 2001:500:1::803f:235#53
Jan 21 19:31:34 SERVER1 named[24210]: error (network unreachable) resolving '108.10.168.192.in-addr.arpa/PTR/IN': 2001:7fd::1#53

Those zones and tables don't exist in my /var/named/ directory and this is seriously bogging down my network. Any help is appreciated!

-Kwazii

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2 Answers 2

You may not be hosting those reverse zones authoritatively, but it's very likely that this is legitimate traffic if you have networks within 192.168.10-11 space. Machines are going to ask for them, it's as simple as that.

Your nameserver is trying to recursively resolve in-addr.arpa space, and you're getting sent to IANA's IPV6 root servers, which those are the IPV6 addresses for. If your kernel appears to support IPv6, named is probably getting confused by this. You can try appending -4 to your startup options in the appropriate config file to make those messages go away, though you really shouldn't be letting in-addr.arpa queries leak out onto the internet if you can help it. Even if you make this error vanish from your logs, all of the queries are still going to hit ARIN's blackhole servers.

Without additional evidence, I am very disinclined to believe that this is the cause of your performance problem.

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It sounds like you have disabled empty zones and as a result the PTR queries for your RFC 1918 zones (in this case the 192.168.0.0/16 private address space) are leaking from your NAT, which is a bad thing for several reasons.

You should probably be serving reverse-lookup zones for any part of the address space you are actually using and might want to turn on "empty-zones-enable yes;"

See also: section 6.2.16.17 of the BIND 9 Administrator's Reference Manual (BIND9 ARM)

You could also be running a very old version of BIND. Empty zones are turned on by default in recent versions of BIND.

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Thank you Michael, I will be testing this later and i will update the thread! –  Kwazii Jan 22 '13 at 22:11
    
@Kwazii Again, I note this will not be the cause of your network performance problem. Please provide some additional research if you want your actual problem to be addressed. –  Andrew B Jan 22 '13 at 22:45
    
Hello Andrew, I assume this is causing my network performance because when the chain of "network host unreachable" happen link with outage times one of the applications run into connection issues. –  Kwazii Jan 23 '13 at 19:40
    
Does your server have an IPv6 address that it utilizes as part of its default route? If so, the log messages are a symptom of the same problem, not the actual cause. –  Andrew B Jan 24 '13 at 22:11

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