Added check if server down

failover-proxy-init

 #!/bin/sh
 UCI_GET="/sbin/uci -q get"
-
+ERRORS="403 404 500 501 502 503"
 ADDRESS=`$UCI_GET proxy.failover.address`
 generate_config() {
 #ADDRESS="10.1.1.1;10.1.1.2;10.1.1.3"
-	IFS=";" read -a ADDRESSES <<< "$ADDRESS"
-	length=${#ADDRESSES[*]}
-	config="location / {proxy_intercept_errors on;proxy_pass ${ADDRESSES[0]};error_page 403 404 = @fallback1;}"
-	for ((i=1; i<$length-1; i++)); do
-	    config="$config location @fallback$i {proxy_intercept_errors on;proxy_pass "
-	    config="$config${ADDRESSES[$i]}"
-	    config="$config;error_page 403 404 = @fallback$((i+1));}"
-	done
-	
-	config="$config location @fallback$i {proxy_pass ${ADDRESSES[-1]};}"
+    IFS=";" read -a ADDRESSES <<< "$ADDRESS"
+    length=${#ADDRESSES[*]}
+    config="location / {proxy_intercept_errors on;proxy_pass ${ADDRESSES[0]};error_page $ERRORS = @fallback1;}"
+    for ((i=1; i<$length-1; i++)); do
+        config="$config location @fallback$i {proxy_intercept_errors on;proxy_pass "
+        config="$config${ADDRESSES[$i]}"
+        config="$config;error_page $ERRORS = @fallback$((i+1));}"
+    done
+
+    config="$config location @fallback$i {proxy_pass ${ADDRESSES[-1]};}"
 }
 
 generate_config