Port forwarding 450BX1 or 450TC2

Discussion in 'Airtel Broadband' started by sjain2411, Jul 17, 2013.

  1. sjain2411

    sjain2411 New Member

    Hi There,

    I have been trying to setup port forwarding for past one week with no success. Can someone guide me here. I understand there is a step missing which I am not able to identify.

    I am going to Advanced Setup --> NAT --> Virtual Server and adding new rule to forward external port to internal port on statis IP of my DVR. Scenarios I have tried so far


    1. Forward external port 80 to internal 80 on DVR IP. The moment you add this rule, the web URL for router shifts to port 8080 for external world and yes, I can access router home page at port 8080 using my data card (externally, with wifi disconnected from laptop). But not able to connect to port 80 from outside which technically should be routed to 80 of my home security DVR. Also can telnet to port 8080 from outside, but port 80 just doesn't respond.


    2. Forward external port 8080 to internal port 80 on DVR IP. Router home page stays at port 80 from outside and yes, can access router home page at port 80 from outside, can telnet to port 80 from outside, but 8080 doesn't respond.


    3. Forward external port 8080 to internal 8080 on DVR IP, with DVR home page port changed to 8080. Can connect to router home page from outside at port 80, using Tata data card, can talent to port 80 as well, but port 8080 - no response.


    4. Removed all port forwarding rules, kept DVR home page at 8080, added DVR IP to DMZ servers assuming all requests to unconfgured ports would land to this IP, but still no response on 8080 from outside.


    Out of options now, need some guidance.

    Thanks
    Sanjay
  2. Admin

    Admin Administrator Staff Member

    I am too simple to be able to understand whats going on. I would love to help by suggesting a simpler and more robust way to achieve what you are trying to achieve. It would help if you could elaborate what you are trying to achieve. If you are trying to set up an IP camera then there are better ways of doing it but before I throw in my suggestions I would like to hear what you really trying to do.
  3. sjain2411

    sjain2411 New Member

    Yes, you got it right. I am trying to setup my home security DVR for remote viewing. It was working fine with MTNL DSL connection on DLink router, but post swiching to Airtel, same procedure is not working on Beetel 450BX1 or TC2 modem. It looks starnge as ideally it should work. Moreover I am able to telnet to port 80 or 8080 on router from outside when router admin page points to this port. Thar means something is wrong with router config which is not allowing port forwarding and reaching the next hop - home DVR.

    Thanks,
    Sanjay
  4. Admin

    Admin Administrator Staff Member

    Does this router have an inbuilt firewall? If it does then is it turned on by any chance?


    From reading your posts it is evident that both port 80 and 8080 are not blocked by Airtel but your router is actively refusing connections to one or the other. There appears to be a rule in the inbuilt firewall that seems to be the culprit.

    The title of the thread says : 450BX1 or 450TC2
    Are these two different modems with inbuilt routers or what?
  5. sjain2411

    sjain2411 New Member

    I also suspect that. There is some sort of rule on these routers that is blocking external traffic from getting into LAN side of it.

    Yes, these are two different ADSL Router models that I tried on and could not enable port forwarding on either of them. I am posting the output of iptables from 450BX1 router below. Check if you find something that is stopping it. 192.168.1.10 is the IP of DVR.

    =============================================================================
    > iptables --list
    Chain INPUT (policy ACCEPT)
    target prot opt source destination

    Chain FORWARD (policy ACCEPT)
    target prot opt source destination
    ACCEPT udp -- anywhere 192.168.1.10 udp dpt:webcache
    ACCEPT tcp -- anywhere 192.168.1.10 tcp dpt:webcache
    DROP tcp -- anywhere anywhere tcp flags:SYN,RST,ACK/SYN #conn/32 > 1000
    TCPMSS tcp -- anywhere anywhere tcp flags:SYN,RST/SYN TCPMSS clamp to PMTU
    TCPMSS tcp -- anywhere anywhere tcp flags:SYN,RST/SYN TCPMSS clamp to PMTU

    Chain OUTPUT (policy ACCEPT)
    target prot opt source destination
    DROP all -- anywhere 239.255.255.250
    >
    =============================================================================


    Thanks,
    Sanjay
  6. sjain2411

    sjain2411 New Member

    I just tried removing all NAT settings and adding DVR to DMZ host. Changed DVR port to 1111 to ensure it is non-standard and doesn't conflict with any of ADSL router ports. Still no response from outside.

    I am tired of options now. Can anyone with Airtel BB in Delhi try port forwarding and let me know the results. Seems Airtel is blocking it at firmware level. If you can share the trusted non-airtel site with 450BX1 firmware, I would like to try that.

    Thanks,
    Sanjay
  7. Admin

    Admin Administrator Staff Member

    I give up. I have no clue how to resolve this to be honest as you have tried everything that comes to my mind already. I will see if I can get a networking engg to have a look at this thread during the day.
  8. Admin

    Admin Administrator Staff Member

    Also I wouldnt try another firmware unless we know for sure that its Airtel's firmware which is causing this problem. You could end up with a very broken modem trying to get another firmware working with it.


    Anyone?
  9. sjain2411

    sjain2411 New Member

    Would be great if someone from networking team look into this. I tried to enabling firewall on modem and it stopped everything from outside, even admin page and ping. After disabling firewall it is back to where we were. So firewall is not an issue. I have not tried playing around with iptable though from command line, will try that over the weekend.

    Seems not many users of port forwarding on this forum or they would have jumped in by now. Let's wait & watch.
  10. sjain2411

    sjain2411 New Member

    Would be great if someone from networking team look into this. I tried to enabling firewall on modem and it stopped everything from outside, even admin page and ping. After disabling firewall it is back to where we were. So firewall is not an issue. I have not tried playing around with iptable though from command line, will try that over the weekend.

    Seems not many users of port forwarding on this forum or they would have jumped in by now. Let's wait & watch.

    I have two modems as of now - 450BX1 and 450TC2, both exhibit the same behaviour ....... wierd !!
  11. sjain2411

    sjain2411 New Member

    You will find the problem where you least suspect.

    Default gateway on DVR was set to 192.168.1.254 instead of 192.168.1.1. I realized this while changing DVR IP config from static to DHCP. Port forwarding is working as expected.

    Thanks for all you attention and support.

    -Sanjay Kumar

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