diff --git a/lib/types/hosts.go b/lib/types/hosts.go
index ddd084704f1..b92e2109abc 100644
--- a/lib/types/hosts.go
+++ b/lib/types/hosts.go
@@ -97,7 +97,7 @@ type Hosts struct {
 // NewHosts returns new Hosts from given addresses.
 func NewHosts(source map[string]Host) (*Hosts, error) {
 	h := &Hosts{
-		source: source,
+		source: toLowerKeys(source),
 		n: &trieNode{
 			children: make(map[rune]*trieNode),
 		},
@@ -113,6 +113,14 @@ func NewHosts(source map[string]Host) (*Hosts, error) {
 	return h, nil
 }
 
+func toLowerKeys(source map[string]Host) map[string]Host {
+	result := make(map[string]Host, len(source))
+	for k, v := range source {
+		result[strings.ToLower(k)] = v
+	}
+	return result
+}
+
 // Regex description of domain(:port)? pattern to enforce blocks by.
 // Global var to avoid compilation penalty at runtime.
 // Based on regex from https://stackoverflow.com/a/106223/5427244
diff --git a/lib/types/hosts_test.go b/lib/types/hosts_test.go
index b6eb46b289e..13f1564ef9e 100644
--- a/lib/types/hosts_test.go
+++ b/lib/types/hosts_test.go
@@ -49,6 +49,7 @@ func TestHosts(t *testing.T) {
 		"specific.wildcard.io":   {IP: net.ParseIP("90.100.110.120")},
 		"*wildcard-2.io":         {IP: net.ParseIP("13.14.15.16")},
 		"specific.wildcard-2.io": {IP: net.ParseIP("130.140.150.160")},
+		"with-UPPER-case.io":     {IP: net.ParseIP("17.18.19.20")},
 
 		// IPv6
 		"simple-ipv6.io":              {IP: net.ParseIP("aa::bb")},
@@ -77,6 +78,8 @@ func TestHosts(t *testing.T) {
 				{"only-port.io", "", NotInHosts},
 				{"only-port.io:443", "5.6.7.8:8443", DifferentPortMapping},
 				{"only-port.io:9999", "", NotGivenPortMapping},
+				{"with-upper-case.io", "17.18.19.20:0", EmptyPortMapping},
+				{"with-UPPER-case.io", "17.18.19.20:0", EmptyPortMapping},
 			}
 			runTcs(t, hosts, tcs)
 		})