diff --git a/contrib/guam.service b/contrib/guam.service
index c21da29..eb230e5 100644
--- a/contrib/guam.service
+++ b/contrib/guam.service
@@ -1,18 +1,19 @@
 [Unit]
 Description=Intelligent IMAP Reverse Proxy
 After=syslog.target
 
 [Service]
 ExecStart=/usr/sbin/guam foreground
 Restart=always
 StandardOutput=syslog
 SyslogIdentifier=guam
 Environment=HOME=/opt/kolab_guam/
+LimitNOFILE=1048576
 
 # No proper setuid/setgid in guam yet. See T971.
 #User=guam
 #Group=guam
 
 [Install]
 WantedBy=multi-user.target