diff --git a/sessions/cookie.go b/sessions/cookie.go
index c6766a09..c7a65026 100644
--- a/sessions/cookie.go
+++ b/sessions/cookie.go
@@ -52,37 +52,7 @@ func RemoveCookie(ctx context.Context, config Config) {
 	cookie.MaxAge = -1
 	cookie.Value = ""
 	cookie.Path = "/"
-
-	if !config.DisableSubdomainPersistence {
-
-		requestDomain := ctx.Host()
-		if portIdx := strings.IndexByte(requestDomain, ':'); portIdx > 0 {
-			requestDomain = requestDomain[0:portIdx]
-		}
-		if IsValidCookieDomain(requestDomain) {
-
-			// RFC2109, we allow level 1 subdomains, but no further
-			// if we have localhost.com , we want the localhost.cos.
-			// so if we have something like: mysubdomain.localhost.com we want the localhost here
-			// if we have mysubsubdomain.mysubdomain.localhost.com we want the .mysubdomain.localhost.com here
-			// slow things here, especially the 'replace' but this is a good and understable( I hope) way to get the be able to set cookies from subdomains & domain with 1-level limit
-			if dotIdx := strings.LastIndexByte(requestDomain, '.'); dotIdx > 0 {
-				// is mysubdomain.localhost.com || mysubsubdomain.mysubdomain.localhost.com
-				s := requestDomain[0:dotIdx] // set mysubdomain.localhost || mysubsubdomain.mysubdomain.localhost
-				if secondDotIdx := strings.LastIndexByte(s, '.'); secondDotIdx > 0 {
-					//is mysubdomain.localhost ||  mysubsubdomain.mysubdomain.localhost
-					s = s[secondDotIdx+1:] // set to localhost || mysubdomain.localhost
-				}
-				// replace the s with the requestDomain before the domain's siffux
-				subdomainSuff := strings.LastIndexByte(requestDomain, '.')
-				if subdomainSuff > len(s) { // if it is actual exists as subdomain suffix
-					requestDomain = strings.Replace(requestDomain, requestDomain[0:subdomainSuff], s, 1) // set to localhost.com || mysubdomain.localhost.com
-				}
-			}
-			// finally set the .localhost.com (for(1-level) || .mysubdomain.localhost.com (for 2-level subdomain allow)
-			cookie.Domain = "." + requestDomain // . to allow persistence
-		}
-	}
+	cookie.Domain = FormatCookieDomain(ctx, config.DisableSubdomainPersistence)
 
 	AddCookie(ctx, cookie, config.AllowReclaim)
 
@@ -121,3 +91,37 @@ func IsValidCookieDomain(domain string) bool {
 
 	return true
 }
+
+func FormatCookieDomain(ctx context.Context, DisableSubdomainPersistence bool) string {
+	if !DisableSubdomainPersistence {
+
+		requestDomain := ctx.Host()
+		if portIdx := strings.IndexByte(requestDomain, ':'); portIdx > 0 {
+			requestDomain = requestDomain[0:portIdx]
+		}
+		if IsValidCookieDomain(requestDomain) {
+
+			// RFC2109, we allow level 1 subdomains, but no further
+			// if we have localhost.com , we want the localhost.cos.
+			// so if we have something like: mysubdomain.localhost.com we want the localhost here
+			// if we have mysubsubdomain.mysubdomain.localhost.com we want the .mysubdomain.localhost.com here
+			// slow things here, especially the 'replace' but this is a good and understable( I hope) way to get the be able to set cookies from subdomains & domain with 1-level limit
+			if dotIdx := strings.LastIndexByte(requestDomain, '.'); dotIdx > 0 {
+				// is mysubdomain.localhost.com || mysubsubdomain.mysubdomain.localhost.com
+				s := requestDomain[0:dotIdx] // set mysubdomain.localhost || mysubsubdomain.mysubdomain.localhost
+				if secondDotIdx := strings.LastIndexByte(s, '.'); secondDotIdx > 0 {
+					//is mysubdomain.localhost ||  mysubsubdomain.mysubdomain.localhost
+					s = s[secondDotIdx+1:] // set to localhost || mysubdomain.localhost
+				}
+				// replace the s with the requestDomain before the domain's siffux
+				subdomainSuff := strings.LastIndexByte(requestDomain, '.')
+				if subdomainSuff > len(s) { // if it is actual exists as subdomain suffix
+					requestDomain = strings.Replace(requestDomain, requestDomain[0:subdomainSuff], s, 1) // set to localhost.com || mysubdomain.localhost.com
+				}
+			}
+			// finally set the .localhost.com (for(1-level) || .mysubdomain.localhost.com (for 2-level subdomain allow)
+			return "." + requestDomain // . to allow persistence
+		}
+	}
+	return ""
+}
diff --git a/sessions/sessions.go b/sessions/sessions.go
index 91f88c93..a490ba8a 100644
--- a/sessions/sessions.go
+++ b/sessions/sessions.go
@@ -2,7 +2,6 @@ package sessions
 
 import (
 	"net/http"
-	"strings"
 	"time"
 
 	"github.com/kataras/iris/context"
@@ -44,37 +43,7 @@ func (s *Sessions) updateCookie(ctx context.Context, sid string, expires time.Du
 
 	cookie.Value = sid
 	cookie.Path = "/"
-	if !s.config.DisableSubdomainPersistence {
-
-		requestDomain := ctx.Host()
-		if portIdx := strings.IndexByte(requestDomain, ':'); portIdx > 0 {
-			requestDomain = requestDomain[0:portIdx]
-		}
-		if IsValidCookieDomain(requestDomain) {
-
-			// RFC2109, we allow level 1 subdomains, but no further
-			// if we have localhost.com , we want the localhost.cos.
-			// so if we have something like: mysubdomain.localhost.com we want the localhost here
-			// if we have mysubsubdomain.mysubdomain.localhost.com we want the .mysubdomain.localhost.com here
-			// slow things here, especially the 'replace' but this is a good and understable( I hope) way to get the be able to set cookies from subdomains & domain with 1-level limit
-			if dotIdx := strings.LastIndexByte(requestDomain, '.'); dotIdx > 0 {
-				// is mysubdomain.localhost.com || mysubsubdomain.mysubdomain.localhost.com
-				s := requestDomain[0:dotIdx] // set mysubdomain.localhost || mysubsubdomain.mysubdomain.localhost
-				if secondDotIdx := strings.LastIndexByte(s, '.'); secondDotIdx > 0 {
-					//is mysubdomain.localhost ||  mysubsubdomain.mysubdomain.localhost
-					s = s[secondDotIdx+1:] // set to localhost || mysubdomain.localhost
-				}
-				// replace the s with the requestDomain before the domain's siffux
-				subdomainSuff := strings.LastIndexByte(requestDomain, '.')
-				if subdomainSuff > len(s) { // if it is actual exists as subdomain suffix
-					requestDomain = strings.Replace(requestDomain, requestDomain[0:subdomainSuff], s, 1) // set to localhost.com || mysubdomain.localhost.com
-				}
-			}
-			// finally set the .localhost.com (for(1-level) || .mysubdomain.localhost.com (for 2-level subdomain allow)
-			cookie.Domain = "." + requestDomain // . to allow persistence
-		}
-	}
-
+	cookie.Domain = FormatCookieDomain(ctx, s.config.DisableSubdomainPersistence)
 	cookie.HttpOnly = true
 	// MaxAge=0 means no 'Max-Age' attribute specified.
 	// MaxAge<0 means delete cookie now, equivalently 'Max-Age: 0'