# Fix DNS errors on Stripe Terminal JavaScript SDK

## Overview
Some DNS providers block DNS resolution of local IP addresses. You can check whether DNS resolution is successful by going to the [**Settings**](https://stripe.com/docs/terminal/payments/setup-reader/bbpos-wisepos-e#settings) on your reader, selecting **Diagnostics**, and checking the DNS resolution test results. Stripe Terminal uses the partially qualified domain name `*.[random-string].device.stripe-terminal-local-reader.net`, which resolves to the local IP address of your BBPOS WisePOS E or S700/S710. If your DNS provider blocks local IP resolution, change your network settings to use one of the following DNS providers:
* [Cloudflare DNS](https://1.1.1.1/dns/) (1.1.1.1 and 1.0.0.1)
* [Google Public DNS](https://developers.google.com/speed/public-dns) (8.8.8.8 and 8.8.4.4)
This only impacts the Stripe Terminal JavaScript SDK, so if you're using the server-driven integration or any of our mobile SDKs (Android, iOS, React Native) to communicate with our smart readers, this won't impact you.
## If you need to change DNS settings
If you have access to your router settings, we recommend making this change on your router at the location where you're accepting in-person payments. This way, all devices at that location will receive the correct DNS configuration.
Otherwise, use the instructions below depending on the system of your point-of-sale device.
### Changing DNS on the router
If you have more than one smart readers, you may prefer to modify the DNS of your WiFi on your network router to avoid changing the DNS settings on each point of sale. There should be no impact on any of your regular internet traffic by changing the router's DNS to any well-known providers listed above.
Example instructions on changing the DNS settings on your router are available [here](https://www.howtogeek.com/167533/the-ultimate-guide-to-changing-your-dns-server#:~:text=To%20change%20your%20DNS%20server%2C%20head%20to%20Settings,it%20to%20%E2%80%9CStatic%E2%80%9D%20instead%20of%20the%20default%20DHCP.).
### Changing DNS on the device
#### Microsoft Windows
If you're using a Windows machine as your point of sale, try Microsoft's intrcutions to [change DNS settings](https://support.microsoft.com/en-us/windows/change-tcp-ip-settings-bd0a07af-15f5-cd6a-363f-ca2b6f391ace). You may need device administrator permissions to modify DNS settings. You will need to change the DNS on each Windows machine used with Stripe Terminal.
#### Apple devices
If you're using a Mac, follow Apple's instructions to [change your point of sale DNS settings in macOS](https://support.apple.com/guide/mac-help/change-dns-settings-network-preferences-mac-mh14127/mac). If you're using an iPad, follow [these steps](https://appleinsider.com/articles/18/04/22/how-to-change-the-dns-server-used-by-your-iphone-and-ipad). You may need device admin permissions to modify the DNS. You'll need to change the DNS on each Apple device you're using as a point of sale.
### Changing DNS in the browser
Most modern browsers such as Google Chrome or Firefox support modifying the DNS in use directly in the browser by using DNS over HTTPS. See [detailed instructions](https://developers.cloudflare.com/1.1.1.1/encryption/dns-over-https/encrypted-dns-browsers/) on modifying the DNS your browser uses.
* You'll need to change the DNS on each browser you use as your point of sale.
* Depending on your network configuration, you may also need to adjust the DNS settings on your router alongside the browser.
**Firefox**
Screenshot of Firefox DNS settings
**Chrome**
`chrome://settings/security`
Screenshot of Chrome DNS settings
**Apple Safari**
Safari doesn't support DNS over HTTPS, therefore any DNS changes have to be performed on the device itself.
## Verify root certificate
If you're using an older system platform with the Stripe Terminal SDK and having connection issues with your Internet Reader (WisePOS E or S700), make sure your system has the [ISRG Root X1](https://letsencrypt.org/certificates/#root-certificates) root certificate installed.
## Additional information
* [BBPOS WisePOS E troubleshooting](https://stripe.com/docs/terminal/readers/bbpos-wisepos-e#troubleshooting)
* [S700/S710 troubleshooting](https://docs.stripe.com/terminal/readers/stripe-reader-s700#troubleshooting)
* My point-of-sale application cannot connect to the reader
* Ensuring Stripe Terminal JavaScript SDK Functionality on macOS 15