diff --git a/conf/nginx.conf b/conf/nginx.conf
index 7414cd34..db1a38a2 100644
--- a/conf/nginx.conf
+++ b/conf/nginx.conf
@@ -52,5 +52,7 @@ server {
 		fastcgi_param SCRIPT_FILENAME /usr/local/bin/mailinabox-webfinger.php;
 		fastcgi_pass unix:/tmp/php-fastcgi.www-data.sock;
 	}
+
+	# ADDITIONAL DIRECTIVES HERE
 }
 
diff --git a/management/web_update.py b/management/web_update.py
index e85e0d02..78659fed 100644
--- a/management/web_update.py
+++ b/management/web_update.py
@@ -2,7 +2,7 @@
 # domains for which a mail account has been set up.
 ########################################################################
 
-import os, os.path
+import os, os.path, re, rtyaml
 
 from mailconfig import get_mail_domains
 from utils import shell, safe_domain_name, sort_domains
@@ -67,6 +67,20 @@ def make_domain_config(domain, template, env):
 	nginx_conf = nginx_conf.replace("$ROOT", root)
 	nginx_conf = nginx_conf.replace("$SSL_KEY", ssl_key)
 	nginx_conf = nginx_conf.replace("$SSL_CERTIFICATE", ssl_certificate)
+
+	# Add in any user customizations.
+	nginx_conf_parts = re.split("(# ADDITIONAL DIRECTIVES HERE\n)", nginx_conf)
+	nginx_conf_custom_fn = os.path.join(env["STORAGE_ROOT"], "www/custom.yaml")
+	if os.path.exists(nginx_conf_custom_fn):
+		yaml = rtyaml.load(open(nginx_conf_custom_fn))
+		if domain in yaml:
+			yaml = yaml[domain]
+			if "proxy" in yaml:
+				nginx_conf_parts[1] += "\tlocation / {\n\t\tproxy_pass %s;\n\t}\n" % yaml["proxy"]
+
+	# Put it all together.	
+	nginx_conf = "".join(nginx_conf_parts)
+
 	return nginx_conf
 
 def get_web_root(domain, env):