diff --git a/.golangci.yml b/.golangci.yml
index 19d1ab4f3..621db83ba 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -2,6 +2,7 @@ version: "2"
 linters:
   default: none
   enable:
+    - canonicalheader
     - copyloopvar
     - govet
     - ineffassign
diff --git a/plugin/pkg/doh/doh.go b/plugin/pkg/doh/doh.go
index 35764eeae..d125dd681 100644
--- a/plugin/pkg/doh/doh.go
+++ b/plugin/pkg/doh/doh.go
@@ -45,8 +45,8 @@ func NewRequest(method, url string, m *dns.Msg) (*http.Request, error) {
 			return req, err
 		}
 
-		req.Header.Set("content-type", MimeType)
-		req.Header.Set("accept", MimeType)
+		req.Header.Set("Content-Type", MimeType)
+		req.Header.Set("Accept", MimeType)
 		return req, nil
 
 	case http.MethodPost:
@@ -59,8 +59,8 @@ func NewRequest(method, url string, m *dns.Msg) (*http.Request, error) {
 			return req, err
 		}
 
-		req.Header.Set("content-type", MimeType)
-		req.Header.Set("accept", MimeType)
+		req.Header.Set("Content-Type", MimeType)
+		req.Header.Set("Accept", MimeType)
 		return req, nil
 
 	default: