diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000..408c0f3
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,4 @@
+[env]
+# Each interface needs 1 IP allocated to the WireGuard peer IP.
+# "8" = 7 tunnels per protocol.
+SMOLTCP_IFACE_MAX_ADDR_COUNT = "8"
diff --git a/README.md b/README.md
index 60b4c15..413e6d0 100644
--- a/README.md
+++ b/README.md
@@ -126,6 +126,14 @@ INFO  onetun::tunnel > Tunneling TCP [127.0.0.1:8081]->[192.168.4.4:8081] (via [
 
 ... would open TCP ports 8080 and 8081 locally, which forward to their respective ports on the different peers.
 
+#### Maximum number of tunnels
+
+`smoltcp` imposes a compile-time limit on the number of IP addresses assigned to an interface. **onetun** increases
+the default value to support most use-cases. In effect, the default limit on the number of **onetun** peers
+is **7 per protocol** (TCP and UDP).
+
+Should you need more unique IP addresses to forward ports to, you can increase the limit in `.cargo/config.toml` and recompile **onetun**.
+
 ### UDP Support
 
 **onetun** supports UDP forwarding. You can add `:UDP` at the end of the port-forward configuration, or `UDP,TCP` to support