diff --git a/interface/web/dns/dns_spf_edit.php b/interface/web/dns/dns_spf_edit.php
index 32955c4b8e74cbe292a2d5775263736b3038f32a..e95227ab393223e916137855653624548565a1df 100644
--- a/interface/web/dns/dns_spf_edit.php
+++ b/interface/web/dns/dns_spf_edit.php
@@ -202,7 +202,7 @@ class page_action extends tform_actions {
 		if (!empty($spf_domain)) {
 			$rec = split(' ', $spf_domain);
 			foreach ($rec as $domain) {
-				if (preg_match('/^[a-zA-Z0-9\\.\\-\\*]{0,64}$/', $domain))
+				if (preg_match('/_^[a-zA-Z0-9\\.\\-\\*]{0,64}$/', $domain))
 					$spf_record[] = 'include:' . $domain;
 				else {
 					if (isset($app->tform->errorMessage )) $app->tform->errorMessage .= '<br/>' . $app->tform->wordbook["spf_invalid_domain_txt"]. $domain;