> Fetch clean Markdown by appending `.md` to any page URL under https://signalwire.com/docs or requesting it with the HTTP header `Accept: text/markdown`. The root index at https://signalwire.com/docs/llms.txt lists the available documentation indexes.

# Allow SignalWire IPs through your firewall

SignalWire does not publish a static list of IP addresses. Customers should periodically resolve the following domains and update their firewall rules accordingly:

```bash
dig sip.signalwire.com | egrep ^sip | awk '{ print $5 }' | xargs -n1 -I{} iptables -A INPUT -s {} -j ACCEPT

dig relay.signalwire.com | egrep ^relay | awk '{ print $5 }' | xargs -n1 -I{} iptables -A INPUT -s {} -j ACCEPT

dig firewall.signalwire.com | egrep ^firewall | awk '{ print $5 }' | xargs -n1 -I{} iptables -A INPUT -s {} -j ACCEPT
```

> **Warning**
>
> Use domain-based authorization rather than hardcoded IPs — addresses are subject to change. Media originates from a wide variety of locations and is non-deterministic.