diff -up mrtg-2.17.4/bin/cfgmaker.orig mrtg-2.17.4/bin/cfgmaker
--- mrtg-2.17.4/bin/cfgmaker.orig	2015-09-07 13:12:23.960003553 +0200
+++ mrtg-2.17.4/bin/cfgmaker	2015-09-07 13:13:16.694253515 +0200
@@ -1369,22 +1369,23 @@ sub addrouter() {
             # tenderly and populate the $$flags{}{} hashes accordingly.
             for my $g (@{$$opt{"global"}}) {
                 my ($t,$fs);
-                $g =~ /^options\[([_^\$])\]:\s*(.*)$/i;
-                $t = $1;
-                $fs = $2;
-                $t =~ s/_/default/;
-                $t =~ s/\^/prepend/;
-                $t =~ s/\$/append/;
+                if ($g =~ /^options\[([_^\$])\]:\s*(.*)$/i) {
+                    $t = $1;
+                    $fs = $2;
+                    $t =~ s/_/default/;
+                    $t =~ s/\^/prepend/;
+                    $t =~ s/\$/append/;
 
-                # If a line like "options[X]:" is found clear
-                # all flags for that category and then go to next
-                # --global 'Options[..' line if any.
-                if ($fs =~ /^\s*$/) {
-                    $$flags{$t} = {};
-                    next;
-                } else {
-                    for my $f (split /\s*,\s*/,$fs) {
-                        $$flags{$t}{$f} = "set";
+                    # If a line like "options[X]:" is found clear
+                    # all flags for that category and then go to next
+                    # --global 'Options[..' line if any.
+                    if ($fs =~ /^\s*$/) {
+                        $$flags{$t} = {};
+                        next;
+                    } else {
+                        for my $f (split /\s*,\s*/,$fs) {
+                            $$flags{$t}{$f} = "set";
+                        }
                     }
                 }
             }