# My point-of-sale application cannot connect to the Terminal smart reader using Terminal SDKs

### If you can't connect to a Stripe Terminal Smart reader from your point-of-sale device using one of the Terminal sdks, your network might have a firewall blocking the protocols and ports the devices use to connect to the readers.
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This doesn't apply if you're using our mobile readers (Wisepad3, Stripe reader M2), or using our server-driven integration with our smart readers (WisePOS E, S700/S710).
Make sure the following protocols, ports, and IP addresses are allowlisted within your LAN:
* TCP port 4443
* TCP port 443 (HTTPS)
* UDP port 53 (DNS)
Additionally, allow all [Stripe domains](https://docs.stripe.com/ips) within your firewall settings. If you're prompted with **Set Network Location** on a Windows computer, select the **Work** option. Selecting **Home** will block the network connections required for Stripe Terminal to function.
## **Additional information**
* The Stripe Terminal SDK is encountering missing certificate errors when connecting to an Internet Reader
* Ensuring Stripe Terminal JavaScript SDK Functionality on macOS 15