diff --git a/app/dns/dns.go b/app/dns/dns.go
index 75df565e4..8493972f6 100644
--- a/app/dns/dns.go
+++ b/app/dns/dns.go
@@ -200,9 +200,7 @@ func (s *DNS) lookupIPInternal(domain string, option dns.IPOption) ([]net.IP, er
 	}
 
 	// Normalize the FQDN form query
-	if strings.HasSuffix(domain, ".") {
-		domain = domain[:len(domain)-1]
-	}
+	domain = strings.TrimSuffix(domain, ".")
 
 	// Static host lookup
 	switch addrs := s.hosts.Lookup(domain, option); {
diff --git a/app/reverse/portal.go b/app/reverse/portal.go
index 34066f219..0420fa2f8 100644
--- a/app/reverse/portal.go
+++ b/app/reverse/portal.go
@@ -154,7 +154,7 @@ func (p *StaticMuxPicker) PickAvailable() (*mux.ClientWorker, error) {
 		return nil, newError("empty worker list")
 	}
 
-	var minIdx int = -1
+	var minIdx = -1
 	var minConn uint32 = 9999
 	for i, w := range p.workers {
 		if w.draining {
diff --git a/features/routing/dns/context.go b/features/routing/dns/context.go
index 8dcfe4945..f0a8b05a1 100644
--- a/features/routing/dns/context.go
+++ b/features/routing/dns/context.go
@@ -26,7 +26,7 @@ func (ctx *ResolvableContext) GetTargetIPs() []net.IP {
 	}
 
 	if domain := ctx.GetTargetDomain(); len(domain) != 0 {
-		var lookupFunc func(string) ([]net.IP, error) = ctx.dnsClient.LookupIP
+		var lookupFunc = ctx.dnsClient.LookupIP
 		ipOption := &dns.IPOption{
 			IPv4Enable: true,
 			IPv6Enable: true,
diff --git a/proxy/freedom/freedom.go b/proxy/freedom/freedom.go
index ffbfeb4e1..12b0b6279 100644
--- a/proxy/freedom/freedom.go
+++ b/proxy/freedom/freedom.go
@@ -66,7 +66,7 @@ func (h *Handler) resolveIP(ctx context.Context, domain string, localAddr net.Ad
 		newError("DNS client doesn't implement ClientWithIPOption")
 	}
 
-	var lookupFunc func(string) ([]net.IP, error) = h.dns.LookupIP
+	var lookupFunc = h.dns.LookupIP
 	if h.config.DomainStrategy == Config_USE_IP4 || (localAddr != nil && localAddr.Family().IsIPv4()) {
 		if lookupIPv4, ok := h.dns.(dns.IPv4Lookup); ok {
 			lookupFunc = lookupIPv4.LookupIPv4