Dont accept connections when application down

app/Classes/Protocol/Binkp.php

@@ -168,10 +168,21 @@ final class Binkp extends BaseProtocol
 	 *
 	 * @throws \Exception
 	 */
-	private function binkp_hs(): void
+	private function binkp_hs(): bool
 	{
 		Log::debug(sprintf('%s:+ Starting BINKP handshake',self::LOGKEY));
 
+		if (! $this->originate && $this->down) {
+			Log::info(sprintf('%s:! System down for maintenance',self::LOGKEY));
+
+			$this->msgs(self::BPM_BSY,'RETRY 0600: Down for maintenance, back soon...');
+
+			while ($this->tx_left || $this->mqueue->count())
+				$this->binkp_send();
+
+			return FALSE;
+		}
+
 		if (! $this->originate && $this->capGet(self::F_MD,self::O_WANT)) {
 			$random_key = random_bytes(8);
 			$this->md_challenge = md5($random_key,TRUE);
@@ -206,6 +217,8 @@ final class Binkp extends BaseProtocol
 
 			$this->msgs(self::BPM_ADR,$addresses->pluck('ftn')->join(' '));
 		}
+
+		return TRUE;
 	}
 
 	/**
@@ -1341,7 +1354,8 @@ final class Binkp extends BaseProtocol
 			return self::S_FAILURE;
 
 		$this->force_queue = $force_queue;
-		$this->binkp_hs();
+		if (! $this->binkp_hs())
+			return self::S_FAILURE;
 
 		while (TRUE) {
 			if ((! $this->sessionGet(self::SE_INIT))