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Thread: [RESOLVED] DVR and Port Forwarding

  1. #1

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    Resolved [RESOLVED] DVR and Port Forwarding

    I have been trying in vain to port forward my router but I am not sure what I am doing wrong, it just doesnt work. My router is Prolink Hurricane 9200 and my DVR is Swann's DVR16-Net-Plus. It specifically states in the manual that I should port forward the ports 5000 and 5001 but when I try to use NetViewer to access my public ip there seems to be no response from the DVR...

    Here are pertinent screenshots...
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    Re: DVR and Port Forwarding

    You have conflicting configurations; this is most likely why it is not working. Firstly, you have your port forwarding set up to match ports 5000-5001 but only redirect to port 5000. Secondly you have HTTP matching, well, nothing, thirdly you are trying to filter based on a private address; unless your router forms a LAN to LAN boundary there is no need to do this. Finally, you have set up the IP address as a DMZ server which would in any case make the above configurations redundant.

    Remove the DVR from the DMZ, remove the filtering rule and sort out the forwarding rule and provided the DVR has no Firewall it should work a dream.
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    Re: DVR and Port Forwarding

    Attached are screenshots of my new configuration but still does not work. I'm a noob in these things so pls. guide me.

    Using winsock I tried to connect to the DVR using the public IP, the result is that when I connect to port 80 I am able to connect but using port 5000 or 5001 I cannot connect and encounters this error: "Connection is forcefully rejected", what does that mean? Using the local IP Address of the DVR and port 5000 I am able to establish connection.

    Also attached is the screenshot of the local network setting that works...

    This is a similar setup of the router: http://www.portforward.com/english/r...00/default.htm

    This is the DVR: http://www.swann.com.au/s/products/view/?product=370

    Any guidance will be greatly appreciated!
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    Last edited by dee-u; Aug 26th, 2008 at 01:52 AM.
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    Re: DVR and Port Forwarding

    The port filtering rules are not required, because you have setup your router as a NAT server. To allow access to your LAN server you need port forwarding ONLY. Delete the port filtering rules and see if this makes a difference.

    In addition, ensure there are no other open ports required by your system in order to connect. It might be worth downloading a copy of Wireshark and firing this up while using the application.

    The forcible rejection of packets indicates a firewall intercepted the communications and rejected it with an ICMP packet or reset the attempt to make a connection. There is a small possibility that your ISP is responsible for this; but lets not entertain that idea yet and sort out your configuration first.
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    Re: DVR and Port Forwarding

    I have tried removing the filtering rules as you suggested but still no difference. These are the ports that needs to be opened as I have seen in the help of the product.

    Public Port Private Port Connection type Host IP
    5000 5000 TCP 192.168.1.167 (sample only)
    5001 5001 TCP 192.168.1.167
    5002 5002 TCP 192.168.1.167

    Attached is the screenshot of my latest and only configuration but still it does not work. Using www.canyouseeme.org I am able to test that ports 5000 and 5001 are opened and not being blocked by my ISP but I still cannot establish a remote connection to the DVR using those ports. Strange is if I specify port 80 then I can establish a connection but I cannot not retrieve videos from the DVR, I think I really have to use port 5000/5001 in order to retrieve videos from the DVR.

    I am not sure how to use Wireshark but I have retrieved the ff. message using the command Follow TCP stream. That is when I tried to use ports 5000/5001.

    <HTML><HEAD><TITLE>400 Bad Request</TITLE></HEAD>
    <BODY><H1>400 Bad Request</H1>
    Your client has issued a malformed or illegal request.
    </BODY></HTML>

    This is really frustating, I hope you could show me the way out of this. Is there an application out there that could automatically configure my ports so they are correctly forwarded?
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    Re: DVR and Port Forwarding

    If the help tells you to open ports 5000-5002 for TCP then you have configured your router correctly. It might be worth checking it is TCP and not UDP just to be sure.

    Feel free to send me the IP / host name you are trying to connect through and I will have a look and see what I get from my side. There are three places the data could be blocked the ISP (which you have ruled out), your router (if it is then there is a firmware bug - try upgrading it) or the machine hosting the DVR server software.

    You should check weather or not the DVR has its own Firewall and if somewhat rule sets it uses to determine who can access it. you can check weather the DVR is playing nice be removing all your current forwarding rules and adding its IP address as a DMZ server. If you can access it then it means it is not blocking it, if you cannot then it means that it is.
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    Re: DVR and Port Forwarding

    Hi,

    Some Internet providers out there DO NOT allow requests on port 80. You will use your external IP address, the one found in the status page of the router to connect remotely.

    In other words, when you try to connect to your DVR from a remote location using your external IP address, that "request" is coming into your modem on port 80. This can not be changed. There is a very complicated work around for this which is way beyond the scope of this forum and against most ISP's terms of use policy. Those Internet providers will force you to purchase business class Internet access to allow traffic on port 80.

    AS mentioned in the previous reply, those of us that do this for a living see this all the time. When we sell and install a system, this type of network support is included in the price ( our experience, etc. ).

    But let's assume your ISP allows port 80 traffic. Have you forwarded port 80 to your DVR IP address?? And, you may need to also forward another port setting as well. All of our DVR's use port 8000.

    Our typical set up is as follows using a Linksys Router...

    DVR 80 to 80 both 192.168.1.150
    DVR2 8000 to 8000 both 192.168.1.150

    Make sure you click the "enable" button. Then Save settings.

    Hope this helps????
    Citing the quote above (from CCTV forum, and not my thread), it seems that port 80 must not be blocked also? I am confused, using http://www.canyouseeme.org/ it says that my port 80 is blocked and my port 5000 and 5001 are not blocked but when using the Advanced Port Scanner v.1.3 from www.radmin.com it says my port 80 is open but ports 5000 and 5001 are closed, which should be true among the two? Or do they have different conditions for checking? If the result from www.canyouseeme.org is the one I will rely on then my port 80 is blocked and as stated in the quote above perhaps that is causing my problem? I am no network guy to determine if the above statement is correct or not but it seems he knows what he is talking about.

    I have tried DMZ but still no success. What I will try later on is to try using a different internet connection to access my DVR, there maybe issues if I am using the same internet connection to access my DVR as I have browsed from some forums.
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    VBA Nutter visualAd's Avatar
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    Re: DVR and Port Forwarding

    Can you make a connection on port 80 from the outside? If so then port 80 is not blocked
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    Re: DVR and Port Forwarding

    Using winsock

    Code:
    Winsock1.RemoteHost = "xxx.xxx.xxx.xxx"
        Winsock1.RemotePort = "80"
    I can establish a connection but why is it that http://www.canyouseeme.org/ tells me that it is closed and so is http://www.yougetsignal.com/tools/open-ports/... ?
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    Re: DVR and Port Forwarding

    Thanks for the PM. I will check how to completel disable my routers firewall, I am not sure how to do it for now. Is it possible that my ISP is causing the dropping of packets?

    How do I actually disable the firewall on my router? Is it on the IP/Port Filtering section?
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    Re: DVR and Port Forwarding

    If you are using NAT then disabling the Firewall will disable NAT; you will need to turn your router to modem only mode. This could be by disabling NAT, disabling the firewall or disabling port forwarding. What router model do you have?
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    Re: DVR and Port Forwarding

    Typing my ip address in your browser would reveal my routers type. If you have time pls. have a look at it and tell me how could I disable the firewall. Thanks for being with me in this predicament....
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    Re: DVR and Port Forwarding

    For further testing, I wish to reroute incoming data in port 80 to port 5001 but I am not sure how, I am trying the code below to imitate how the client application is sending and receiving data from the dvr but as usual I get the "Bad Request" error. As per my understang port 80 is for http so it cannot actually read the message below. I would want it that data that is coming in port 80 be forwarded to 5001 just to test it, what should be the configuration? What would be the local IP Address, the IP address of the DVR or the router? What would be the public and local ports?

    Code:
    Const x As String = "...........|....0000...."
    Winsock1.SendData x
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    Re: DVR and Port Forwarding

    Quote Originally Posted by dee-u
    Typing my ip address in your browser would reveal my routers type. If you have time pls. have a look at it and tell me how could I disable the firewall. Thanks for being with me in this predicament....
    I cannot connect on port 80, so I am none the wiser.
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    Re: DVR and Port Forwarding

    Uh-oh, I thought it would work since from the same LAN and typing my public ip in the browser then my router's setting is shown, I have not been able to test it on different network yet.

    My router is "PROLiNK Hurricane 9200AR Modem/Router", I have given a link in previous posts where the setting is similar.

    Oddly, if I either type 192.168.1.1 or 192.168.2.1 my routers setting is shown, what could be the reason for this?
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    Re: DVR and Port Forwarding

    I have these Remote Access setting, should I change anything on it?
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    Re: DVR and Port Forwarding

    Before proceeding further, may I ask what is the best way to determine if a port is forwarded or not using the same internet connection? Using nmap it tells me that port 80, 21, 23 are all opened and I presume it is because I am in the same internet connection?
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    Re: DVR and Port Forwarding

    Quote Originally Posted by dee-u
    Uh-oh, I thought it would work since from the same LAN and typing my public ip in the browser then my router's setting is shown, I have not been able to test it on different network yet.

    My router is "PROLiNK Hurricane 9200AR Modem/Router", I have given a link in previous posts where the setting is similar.

    Oddly, if I either type 192.168.1.1 or 192.168.2.1 my routers setting is shown, what could be the reason for this?
    It is important to remember that if you are able to access your public address from within your LAN, it does not count as accessing it externally. You are still accessing it through the LAN and will therefore see open ports as if you were in the LAN.
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    Re: DVR and Port Forwarding

    Quote Originally Posted by visualAd
    It is important to remember that if you are able to access your public address from within your LAN, it does not count as accessing it externally. You are still accessing it through the LAN and will therefore see open ports as if you were in the LAN.
    What then could be the best way to test from within the same LAN?
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    Re: DVR and Port Forwarding

    Here are more screenshots of some settings in my router, they are totally greek to me so I am not really sure if I have to change something on these settings so I am attaching them for you to have a look for any suspect setting that I am missing. Another colleague suggested that I enable UPnP and I did but still no success... :-(
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    Re: DVR and Port Forwarding

    Quote Originally Posted by dee-u
    What then could be the best way to test from within the same LAN?
    The other settings you posted looked ok. The best way to test is to test it externally with a dial up connection or a separate DSL connection.
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    Re: DVR and Port Forwarding

    Regarding the quotation on post #7 about port 80 being needed to be open, I am guessing that it is based on scenarios where the client software is 'browser-based' so port 80 should be open, am I right? If the client software is a desktop one then port 80 has nothing to do with it? Port forwarding is greek to me so I am not really sure how it processes messages, does the router actually receives the messages on port 80 or any other port then forwards it to the set ports?
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    Re: DVR and Port Forwarding

    Technically port forwarding is not port forwarding; you may also see it referred to as virtual servers, port translation, NAT forwarding. Its proper name is destination based network address translation or (DNAT). This feature enables the IP and TCP headers of the packets to be translated based on a rule before they are routed; fields which can be change include the IP address and the port numbers.



    The image above shows how DNAT works. In the example a client from on the Internet makes a connection attempt to port 8080 on your public IP address. The router is configured to translate requests on port 8080 to the destination address of 192.168.10 and the destination port to port 80. The router then stores the source address and port of the client and the destination address and port of the server.

    The packet is transformed and sent onto with the new destination address and port. When the server receives it and sends a reply, the packet contains a source address which relates to the LAN address of the server. The information stored by the router is matched against the destination address and port of the client and that of the server. The router then performs another DNAT to translate the source address of the packet back to the public IP and the source port back to port 8080.

    Note how the router forms a link between two networks, your LAN and the Internet and how when using DNAT; the source and destination ports are not required to match.

    DNAT is commonly used because it enables one IP address to be many. When you signed up to your ISP its is likely that they gave you a single static IP address rather than ask you "how many PCs do you have; ok here are 5 IP addresses". When you connect to your ISP the WAN interface on your router will be assigned the static IP address or if you connect using a modem, the modem is assigned that IP address.

    If you want to have multiple PC's use the connection at the same time then you need a router that supports NAT. This is because the DNAT part of the tale only tells half the story. When you have two PC's connected to your router, each will be assigned an IP address in a private address range such as 192.168.x.x; a router should never router a packet from a private network onto a public network such as the Internet. Rather than setup a DNAT rule for every possible host on the Internet (obviously not possible); the router automatically intercepts communications to the outside world changes the source address of the packet to make it look as if it came from your ISP IP address - it is then able to route it. In addition it needs to remember the port number the outbound communications were sent on and modify the destination IP address to that of your PC on the LAN. This is known as IP masquerading and happens as you browse the Internet, talk on MSN, look at porn or check your email - and most people are blissfully unaware of it .



    The above diagram shows how IP masquerading works. Like DNAT, it modifies the source and destination addresses of the packets to facilitate LAN to WAN communication through the router. The web server at the other end has no knowledge that the IP address the request originates is a shared IP address.

    Again here, when the PC within the LAN makes a request to the server on the Internet, it intercepts the communication and stores the source port and source LAN address. It so happens that someone else on the LAN has already made a request on the same source port to the same host; therefore the router chooses a new source port and modifies the source address to match the public address of the router. When the server on the other end replies it sends the response back to the public IP address on the port which the router chose. The router then checks for a match on the source and destination IP addresses and ports. When it finds one it translates the destination address back to the LAN address and the port back to the original port opened by the PC and sends the packet back out on the LAN.

    Aside from the obvious advantage of allowing many hosts to hang off a single IP address. NAT also enhances your security as it creates a barrier between your internal network and the external (dangerous) Internet. By default a router should never forward a packet to or from a private network address. This means that the you can setup things like Windows file sharing on your LAN and worry less about naughty people form the outside print documents on your printer and viewing your virtual filesystems.

    It can only be beneficial to understand behind the scenes how these things work when configuring them. I hope now that the concept of port forward or more rightly DNAT is not longer alien to you.
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  24. #24
    VBA Nutter visualAd's Avatar
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    Re: DVR and Port Forwarding

    To answer your second question; if you access your DVR using:

    http://192.168.1.1/

    Then the browser will automatically connect on port 80.

    If you use something like:


    http://192.168.1.1:8000/

    It will connect on port 8000.
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  25. #25

    Thread Starter
    Software Carpenter dee-u's Avatar
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    Re: DVR and Port Forwarding

    Urghhh, I found out that my original setting was working as I have tested it with another network and it worked. I am not really sure if what is would be wrong but I still put my DVR's IP address in the DMZ and set IP/Port Filtering, since it is working that way I didn't remove those settings anymore, is there any repercussions of using DMZ?

    Thank you so much for accompanying me in this debacle...
    Regards,


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  26. #26
    VBA Nutter visualAd's Avatar
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    Re: [RESOLVED] DVR and Port Forwarding

    There are security considerations. The DVR will be follow accessible if it is in the DMZ and the port forwarding rules will make no difference. I.e: if there is an FTP server on the DVR, then that too will be accessible.
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  27. #27

    Thread Starter
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    Re: [RESOLVED] DVR and Port Forwarding

    Those settings (DMZ, Port Forwarding and IP/Port Filtering) were the ones suggested on the manual so I did follow them blindly. I will later on make further test after removing it from the DMZ.
    Regards,


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