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XG 230 WAN Port 2 Unable to connect to Internet - Wrong DHCP address

Hi all,

We've just purchased a new Sophos XG 230 and have begun the initial set up. We're a small shop so the set up is quite basic. We have the XG connected to a BT Business Hub on port 2 (WAN) which is an ADSL line and the LAN connection on port 1.

We have a range of static public IP addresses from BT (our ISP). The BT Hub has picked up the MAC address of XG port 2 and as per BT's instructions we have assigned one of the public IP's to the mac address. BT advise that the device requiring the static IP (in our case the XG) should be set to automatically obtain an IP address.

I have set the port 2 configuration as DHCP but for some reason it is picking up a DHCP address from our LAN on Port 1. I have no idea how this is happening. I’ve tried setting port 2 to a static IP using the same public IP address but getting 100% packet loss on ping from various domains. BT use PPPoA on our DSL line so we can't set the port to use PPPoE.

Any suggestions? We're very new to XG so apologies if this question has been asked before. I've checked the forums but can't find anything relating to our issue.

Thanks in advance.



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  • Hello,

     

    Please verify your Port2 cable . Is it directly connected to you ISP modem?  If port2 is getting IP from port1, then verify is there is any cable connected between your LAN switch and your ISP modem?

     

    Regards, Ronak.

  • Hi Ronak,

    Thanks for responding. Port 2 is directly connected to our ISP modem. The ISP modem is also connected via a cable to our LAN switch for management purposes. Somehow Port 2 is traversing to the LAN via port 1 but I have no idea why this is happening.

    Thanks

    Lee

  • Hi Lee,

     

    This is expected behaviour. As you XG port2 is connected to switch and on your LAN you have a DHCP server configured.

     

    Your XG Port2 is also indirectly connected to your LAN switch i.e Port2 to ISP modem LAN port and ISP LAN port to LAN switch (Your ISP modem LAN ports is acting as intermediate switch between your XG port2 and your LAN switch). Due to wrong cabling when Port2 is initiating DHCP discovery broadcast request, your LAN DHCP server is responding quick before your ISP DHCP server can respond.

     

    Remove your LAN cable which is connected between your ISP modem and LAN switch. To manage ISP modem you can connect it directly to any system without using your LAN switch.

     

    Good luck!!!

     

    Regards, Ronak.

  • Hi Ronak,

    Thanks for coming back to me. I suspected this is the case, but if we remove the LAN cable from ISP modem to the LAN switch, how we will manage the ISP modem if required? Surely we don't have to walk into the comms room and plug directly into it using a laptop ? 

    I would have thought there are other XG users out there with an XG firewall that is connected to an ISP modem which is in turn connected to the LAN. Maybe I'm wrong.

    Thanks for your help.

    Regards

    Lee

  • Hi Lee,

    Just a quick tip, if you are using Windows as a DHCP you can add port2 mac in filter deny list.

    Please accept the above solutions if it has resolved your issue so that other people in community can find accepted answer.

    Regards, Ronak.

  • Apologies for the late reply to this. We finally had a new leased line installed which at static IP address and now the WAN connection is working fine.

    Thanks for all the help!