diff --git a/ssh/server.go b/ssh/server.go
index 1b7d0a9..ed73736 100644
--- a/ssh/server.go
+++ b/ssh/server.go
@@ -473,6 +473,21 @@ func (p *PartialSuccessError) Is(target error) bool {
        return ok
 }
 
+// BannerError is an error wrapper that can be returned from an authentication
+// callback to send a banner message to the client.
+type BannerError struct {
+       Err     error
+       Message string
+}
+
+func (e *BannerError) Unwrap() error {
+       return e.Err
+}
+
+func (e *BannerError) Error() string {
+       return e.Err.Error()
+}
+
 // ErrNoAuth is the error value returned if no
 // authentication method has been passed yet. This happens as a normal
 // part of the authentication loop, since the client first tries
@@ -756,6 +771,14 @@ userAuthLoop:
                        break userAuthLoop
                }
 
+               var bannerError *BannerError
+               if errors.As(authErr, &bannerError) {
+                       bannerMsg := &userAuthBannerMsg{Message: bannerError.Message}
+                       if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil {
+                               return nil, err
+                       }
+               }
+
                var failureMsg userAuthFailureMsg
 
                var partialSuccess *PartialSuccessError

type ConnMetadataBanner interface {
	ConnMetadata

	// SendAuthBanner sends a banner to the client. This is useful for sending
	// messages during authentication. It is only valid to call this before
	// authentication succeeds.
	SendAuthBanner(banner string) error
}

type ServerConfig struct {
    ....
    // AuthBannerCallback, if present, is called and the return string is sent
   // to the client after a successfull authentication before
   // SSH_MSG_USERAUTH_SUCCESS.
   AuthBannerCallback func(conn ConnMetadata) string
}

// BannerError is an error wrapper that can be returned from an authentication
// callback to send a banner message to the client.
type BannerError struct {
	Err     error
	Message string
}

// BannerError is an error that can be returned by authentication handlers in
// ServerConfig to send a banner message to the client.
type BannerError struct {
	Err     error
	Message string
}

// BannerError is an error that can be returned by authentication handlers in
// ServerConfig to send a banner message to the client.
type BannerError struct {
	Err     error
	Message string
}

func (b *BannerError) Unwrap() error
func (b *BannerError) Error() string