Flip requires a continuous connection between our servers and your apps or browsers. Sometimes, Flip might experience difficulties if it cannot access the necessary resources. This can occur due to restrictions or limitations on your network connection or the environment you are using. The following article outlines the most common causes of these issues.
If you use a Firewall
The URLs or IP addresses listed here may change without prior notice. Please review this page periodically to ensure that the URLs and IPs match those permitted in your system.
To ensure full access to the app and to meet the security requirements, the following IP addresses/domains should be permitted in the firewall:
IP address allowlist
Flip traffic flows in two directions, and each one needs a different firewall rule. Allowlist the set that applies to you:
- Inbound (ingress) — traffic from your clients and browsers to Flip. Allow your network to make outbound connections to the Flip IPs in the first table.
- Outbound (egress) — traffic from Flip to your systems (primarily webhooks). Allow inbound connections to your endpoints that originate from the Flip source IPs in the second table.
Inbound (Ingress) — Client → Flip
| Cluster | Addresses | Ports |
| All | 51.116.174.74 4.184.99.71 20.52.217.177 |
TCP: 443, 80 UDP: 443 |
| EU | 20.113.162.111 | TCP: 443, 80 UDP: 443 |
| AU | 13.73.196.104 | TCP: 443, 80 UDP: 443 |
| US | 52.165.41.163 | TCP: 443, 80 UDP: 443 |
| Testing | 20.170.3.149 | TCP: 443, 80 UDP: 443 |
| Video Conferencing | 142.132.155.149 2a01:4f8:261:2b5a::f0 |
TCP: 80, 443, 5349 UDP: 10000, 3478 |
Outbound (Egress) — Flip → client/system
These are the Flip source IP addresses used for outbound connections (primarily webhooks) sent from Flip to your systems. If you filter inbound traffic, allow connections that originate from these IPs to reach your webhook endpoints (the destination port is whatever your endpoint listens on, typically TCP: 443).
| Cluster | Source IP addresses |
| EU | 20.218.203.73 72.144.65.193 20.113.22.240 98.67.200.117 |
| AU | 20.53.167.75 |
| US | 135.233.121.79 |
| Testing | 20.113.102.226 |
Domains allowlist
| Category | Domain name | Ports |
| Required | *.flipcorp.de | TCP: 443, 80 UDP: 443 |
| Required | *.flip-app.com | TCP: 443, 80 UDP: 443 |
| Required | *.getflip.com | TCP: 443, 80 UDP: 443 |
| Required | *.getflip.cloud | TCP: 443, 80 UDP: 443 |
| Required | .getflip.email | TCP: 443, 80 UDP: 443 |
| Required | *.getflip.link | TCP: 443, 80 UDP: 443 |
| Required | Google FCM Help | See Link. |
| Required | Apple Help | See Link. |
| Optional | Windows Help | See Link. |
| Required | *.getflip.dev | TCP: 443, 80 UDP: 443 |
| Optional. Required if you use Flip CMS (Form and Page builder). |
*.flipcms.de | TCP: 443, 80 UDP: 443 |
| Optional. Required if you use Flip Video Conferences. |
meet.flipapp.de | TCP: 80, 443, 5349 UDP: 10000, 3478 |
If you use a custom domain for Flip, you must allowlist it as well.
Allowlist Email
Depending on your organization's network security requirements, allowlisting specific Flip Email domains is necessary to ensure successful delivery and to avoid the spam folder.
| Category | Sender Domains |
| Required | flip-app.com flipapp.de flipcms.de |
If you use a Proxy
Please ensure that you provide Flip with a by-pass. The following specifications will help.
- The proxy server must support WebSocket connections.
- The proxy HTTP version should be set as 1.2.
- Source IP/host: see the IP addresses above.
- Source port: 80. 80 is used for users that access Flip through HTTP to direct them to HTTPS (blocking 80 is not recommended).
- Destination port: 443 (SSL). 443 is used for HTTPS.
- Protocol: HTTPS
If you use an MDM
Our Android and iOS app uses certificate pinning, also known as SSL Pinning. Please ensure that the SSL certificates for operating the mobile apps with VPN/MDM are not manipulated.
WebSockets
The Flip applications require WebSocket connections. If you're having issues with the Chat or Newsfeed but the settings pages open as expected, this might mean that your connection does not support WebSockets. To test your connection, please open this website on the corresponding device.
If the WebSockets are identified, you'll see the following message:
If the result is different, something in your network is likely blocking WebSocket connections. If this is the case, try the following:
- Use a different network connection
- Use or turn off a VPN
- If you are using a corporate connection, contact your network administrator and ask them to enable WebSocket connections on ports TCP/80, TCP/443 (TLS) and UDP/443. These ports may be closed or filtered within your corporate network for security reasons. To establish a connection, these ports should be open for Flip addresses to access (see the addresses in the "If you use a Firewall" section above).
If the WebSockets test page reports everything's good, but you're still having trouble, please contact Flip Support.
Livestream
To ensure compatibility and quality, configure the following rules:
- Ensure NAT is configured correctly on your network
- Ensure that HTTPS/WSS traffic is allowed, at least for addresses resolved by
*.stream-io-video.com,*.stream-io-api.comand*.getstream.io - Ensure that at least one of the port ranges used by WebRTC is allowed, at least for addresses resolved by
*.stream-io-video.com,*.stream-io-api.comand*.getstream.io - Allow TCP/443 and UDP/443 for all IPs listed by this DNS record
pool.turn.stream-io-video.com(usedig pool.turn.stream-io-video.comto get the list)
This configuration ensures robust connectivity for all clients, maintaining the highest possible video quality across varying network environments.