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AT&T modem passthrough?


I have a situation where my business has signed a contract with Comcast, but it will be 6 weeks before they can do a build out and get a line to my building. In the mean time, I'm having to use AT&T DSL. The modem they have given me is a BGW210-700. I also have a five pack of static IP's and three phone lines from them.

My question is...AT&T says their modem doesn't need to be in IP Passthrough in order for my TZ470 to work. I was told that it needed to be in order to get the Sonicwall to do all my DHCP...and so I can have a static WAN. Keep in mind, AT&T is temporary until Comcast can get to the building. Anyone have advice on how to properly set this up?

Category: Entry Level Firewalls

Best Answers

    SaravananSaravanan Moderator
    Answer ✓

    Hi @JOHNG,

    Thank you for visiting SonicWall Community.

    From your post, in short what I understand is, you have 5 pack of static IP's from AT&T and you need help assigning these IP address on the SonicWall for Internet access. You want SonicWall to perform all DHCP requests for local LAN. Please correct me if I'm wrong.

    If I'm right, you could configure one of the static WAN IP address on the SonicWall leaving the other 4 IP's available and use it for directly accessing local resources on those public IP addresses from external network if needed.

    Please check the below document to assign a static IP address on the SonicWall WAN.

    Please feel free to let me know for questions or clarifications.

    SaravananSaravanan Moderator
    Answer ✓

    Hi @JohnG,

    Thanks for your confirmation. Glad, I was correct. Passthrough mode may vary depending on ISP vendors. Hence verified and got the statement for passthrough from ATT. As per ATT, "IP Passthrough configuration is often times suitable for a business customer desiring to connect 3rd party equipment to AT&T supported equipment. The “IP Passthrough” configuration still allows AT&T support groups to access the AT&T supported equipment while allowing end-users to connect 3rd party equipment in a configuration they desire".

    This is actually we are looking for, to configure a static public IP address on the SonicWall WAN interface. Hence I suggest you to stay with passthrough mode.

    Please feel free to let me know for questions/clarifications.


  • JohnGJohnG Newbie ✭

    Hi @Saravanan

    Yes, you are correct in your understanding. Also, does the AT&T modem have to stay in passthrough mode upon assigning the static IP to the WAN, or should it be taken out of passthrough mode?

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