I am having a problem connecting via odbc to a MySQL database on a remote host. The host said the problem is not on their end. I don't think the problem was on my end becuase I can connect to other MySQL databases using odbc on other hosts.
I downloaded a copy of NMap and rant it on both hosts. The problem host (HOST A) and the host where I CAN connect (HOST B). Port results are below.
Questions: I know MySQL listens on port 3306. As you can see, on Host B, 3306 is shown as OPEN where it is working fine. However 3306 does not even show on the HOST A results. DOes that mean it is definitely NOT open?
What makes a port display here or not display on this scan list. Both hosts have many ports (83 & 89) that are "Not Shown". What keeps them from being shown and if they are not shown, does that mean they are closed?
I am confused by that because on HOST A it does include some "closed" ports on their list.
Just trying to understand this... I already sent them an email that said I didn't think they had 3306 open... so I hope I didn't "jump the gun..."
Scans
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If 'nmap' does not list a part, it does NOT mean that there is not a service on that port. It is possible to have a service running on a port and still hide it from nmap (easily done w/ a firewall/iptables).
In your situation, though, you should be able to connect to port 3306 on Host A.
From host B, do this:
telnet host_a.whatever.com 3306
Do you get anything? If you see "Escape character is '^]'" you connected - otherwise, something is blocking you.
In the connection settings they gave me yesterday they specified 3306. It was odd, it worked fine at 330pm EST when they first sent me the connection settings. I connected, I could readdb tables, etc...
Then I worked on something else, then I went back to this at 530pm EST and could no longer connect and they said they didn't change anything on their end. I believe them, but what could have happned? The website itself is working right now- so mysql must be running, right?
I am guessing based on what you said above that it must have something to do with their firewall? I just don't understand how it would become blocked all of a sudden... unless they did do something and don't even realize that they did...(scratches head...)
"From host B, do this:
telnet host_a.whatever.com 3306"
I am not really versed in this area (i am a programmer!) but I opened on cmd on by own Pc and entered the above, substituting the real address of course, and I got:
Connecting to....www.xxx.com..could not open connection to the host on port 3306: Connect failed
So I presume all this means they have the port blocked.
I did. I just got an email from the owner that said:
'I just tried to telnet both from home and my office and I had no problems connecting (of course I had to add my home IP to the access hosts)
That's the only other thing I can think of.. Can you verify that your IP is valid (within range) with what we put in hosts yesterday? In any case, I don't think it's a port issue."
I know it's valid. What else could be the problem? It's almost like we are at a stalemate.
You should try the telnet again, record the exact time you did so, and ask the owner if they're getting any error messages (like "Access denied for IP xxx.xxx.xxx.xxx") at the the exact time you're attempting your connection.
If they're *not* seeing anything in their log, then the problem is on your side.
Are you running any firewall software?
Yes, you were spot on. Before I even did that I received this email from him from when I did it earlier:
'Sorry, I just noticed that you did try to telnet... I'll keep checking into it and let you know as soon as I know something.'
Any thoughts on what it could be? I would like to suggest some things because I am desperate to get at this data and very much up against a time frame...
Screwed up netmask, missing backslash, who knows - could be anything (having no idea what your host is running for their "access list").
However, I see that you can connect to their host somehow. If you're using ssh, you could try to create your own port forwarding tunnel to MySQL on their host (they'd have to have it turned on, though, and its off by default in sshd_config).
Lot's of fun, though, if it works. ;-)
ssh -v -L 3307:localhost:3306 hosta.whatever.com
(and then leave it connected). If this works, then you can connect to the remote server's MySQL at:
localhost:3307
I didn't. I ran it from my own machine here at my desk and put the server address in ('target'.)
I have like a windows version of it I downloaded when I saw a reference to NMap from another post.
Never even heard of NMap before today!
NMAP
We had to open a port in our firewall. As soon as we did, I connected. Our IT people say there is NO WAY I connected the day before- but I did. I know I did because I wrote down the number of tables in the database. 61, and there is 61. I never would have pushed the issue on their side if it had never worked, becuase I ALWAYS assume the problem is on this end (you have to work here to understand.) But, since I had connected... I was pretty much ASSuming the problem was on the other side. It wasn't.
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by: abodettePosted on 2009-08-28 at 08:09:21ID: 25208468
closed means it checked that port but no application was listening on it. The fact that 3306 does not show up for the host should mean either 1.) mysql is not running and so not listening on port 3306, or 2.) access to port 3306 has been blocked although generally that will show as "filtered" if a firewall is actively blocking it although it might just not show up depending on how the firewall works.
So by all means send the nmap results along saying that port 3306 is not open for requests and suggest they check the status of mysql and any firewall they have on that host. Also ask if maybe they are using a non standard port to run mysql on.