Port 53 Open?

Question

Port 53 Open?

I decided to do a port scan of the new AEBSn (I connected to my neighbors to do it cleanly).

No matter what settings I have turned off, that blasted port 53 is open!

I found another thread below, but it doesn't really look like much of an answer.

And if you try mapping port 53 to anything, you get an error as the guy below did.

I would really rather not have this port open!

http://forums.applenova.com/showthread.php?t=22389

MacBook Pro C2D 15" & iMac CD 17" Mac OS X (10.4.8) 2 Gigs of RAM each

Posted on Feb 11, 2007 2:39 PM

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Answer 1

Quoll

Level 1

8 points

Feb 22, 2007 9:13 PM in response to sumocomputers

I've been trying to get port mapping (port 22) to work ever since I installed this AEBS. However, the device seems to completely ignore any configuration I give it.

I just noticed this thread, since I do indeed have port 53 open. nmap tells me that it's open, and that several others are there, but being filtered:
80, 135, 136, 137, 138, 139, 445, 548, 9100, 9111, 9152, 10000

Intel iMac Core Duo Mac OS X (10.4.8) Airport Extreme Base Station

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Answer 2

Feb 11, 2007 2:46 PM in response to sumocomputers

are you running a DNS server

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Answer 3

Feb 11, 2007 3:29 PM in response to Winston Churchill

No DNS server. And if I was, wouldn't I have to explicitly define that port mapping in the AEBSn?

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Answer 4

Feb 11, 2007 4:14 PM in response to sumocomputers

Not sure but if the extreme is mapping DNS addresses, might that not allow port 53 to appear open

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Answer 5

Feb 11, 2007 7:44 PM in response to Winston Churchill

Not sure but if the extreme is mapping DNS addresses,
might that not allow port 53 to appear open

Yeah, but if it is, where is it mapping it to, and can I turn it off? Or will something bad happen? 😉

Just irritates me that I cannot get a clean port scan on my only exposed connection...

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Answer 6

Feb 11, 2007 7:51 PM in response to sumocomputers

Not really sure like I say why port 53 is open, but:
A DNS address will send your requests to specific server belonging to your ISP, this is sometimes necessary with macs as well as PC's less of the time, it bypasses the request going to a register and then to any of your ISP servers, it may be that specific servers are more compatible for you.

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Answer 7

Feb 11, 2007 8:16 PM in response to sumocomputers

If you're still playing with the Bonjour settings we were talking about in other threads than that would explain why port 53 is open as DNS is required for them to work. Remember that the new AirPort Extreme base station implements NAT Port Mapping Protocol (NAT-PMP) which is designed to automatically open the required ports when a service is enabled.

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Answer 8

Feb 11, 2007 10:05 PM in response to Gino Cerullo

I did think about that, but I reset all to factory and made sure every possible setting that could open me up, was disabled. Still port 53 is open.

Looks like someone else responded to a post regarding the same thing.

I bet if everyone did a port scan from the outside, they will also see port 53 open.

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Answer 9

Feb 12, 2007 5:56 AM in response to sumocomputers

I saw that other thread as well after your post. It seems that the AEBS leaves it open, probably for the Bonjour service to work. I wouldn't loose any sleep over it, DNS is a harmless port to leave open anyway and it's only the router that is answering it.

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Answer 10

Feb 22, 2007 5:03 PM in response to Gino Cerullo

It doesn't matter it shouldn't be broadcasting to the outside unless you tell it to do so. In my opinion this needs to be fixed. I could understand it if Bonjour were running on my comp but it isn't.

Regardless it needs to be fixed and there be a way to turn it off!

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Answer 11

Feb 22, 2007 6:21 PM in response to Marjansar

Yes but if you've enabled bonjour on the router, you have told it to broadcast to the world.

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Answer 12

Feb 22, 2007 10:20 PM in response to Quoll

I've been trying to get port mapping (port 22) to
work ever since I installed this AEBS. However, the
device seems to completely ignore any configuration I
give it.

I just noticed this thread, since I do indeed have
port 53 open. nmap tells me that it's open, and that
several others are there, but being filtered:
80, 135, 136, 137, 138, 139, 445, 548, 9100, 9111,
9152, 10000

Intel iMac Core Duo
Mac OS X (10.4.8) Airport Extreme Base
Station

Are you checking your port scan from inside your network? You really need to connect from the outside.

I have port 22 working no problem. At first it kept refusing the connection (or so I thought). After a tons of futzing, I reset the DSL modem, and it was perfect from then on.

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Answer 13

Quoll

Level 1

8 points

Feb 22, 2007 10:20 PM in response to sumocomputers

Yup, I'm testing from outside my network (what's the point in port forwarding otherwise?) I don't have nmap installed on any machines inside the network, so I can't even make that mistake if I want to.

I guess I could try to reset the modem again. But all was working fine with the Aiport Express I had plugged in a few hours ago.

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Answer 14

Feb 23, 2007 7:47 AM in response to Quoll

Thats just it, people who are not using Bonjour and not have it enabled. They and I are having the port 53 open issue. It needs to addressed and fixed. There is no excuse for ports to be open to the internet without you making that happen. A piece of hardware should not do this on it's own!

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Answer 15

Feb 23, 2007 11:54 AM in response to sumocomputers

From Apple support:

"This is a known issue, which is currently being investigated by engineering. This issue has been filed in our bug database under the original Bug ID# 4975958."

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