diff --git a/src/components/router-config-manager.js b/src/components/router-config-manager.js
index 6503737..57e5a77 100644
--- a/src/components/router-config-manager.js
+++ b/src/components/router-config-manager.js
@@ -31,6 +31,11 @@ let consolePort = Services.prefs.getIntPref("extensions.i2pbutton.console_port_i
 let httpProxyPort = Services.prefs.getIntPref("network.proxy.http_port", 7644)
 let popClientPort = Services.prefs.getIntPref("extensions.i2pbutton.pop3_port", 7645)
 let smtpClientPort = Services.prefs.getIntPref("extensions.i2pbutton.smtp_port", 7646)
+// The preferences code above might return "0" in some cases, we need to override it then.
+if (parseInt(consolePort) == 0) { consolePort=7647 }
+if (parseInt(httpProxyPort) == 0) { httpProxyPort=7644 }
+if (parseInt(popClientPort) == 0) { popClientPort=7645 }
+if (parseInt(smtpClientPort) == 0) { smtpClientPort=7646 }
 
 const defaultWebappsConfig = `# Autogenerated by I2P Browser
 webapps.jsonrpc.startOnLoad=true