diff --git a/default.nix b/default.nix
index 77dca63..43041a5 100644
--- a/default.nix
+++ b/default.nix
@@ -408,12 +408,22 @@ in
       type = types.bool;
       default = false;
       description = ''
-        Whether to enable verbose logging for mailserver related services.  This
+        Whether to enable verbose logging for mailserver related services. This
         intended be used for development purposes only, you probably don't want
         to enable this unless you're hacking on nixos-mailserver.
       '';
     };
 
+    maxConnectionsPerUser = mkOption {
+      type = types.int;
+      default = 100;
+      description = ''
+        Maximum number of IMAP/POP3 connections allowed for a user from each IP address.
+        E.g. a value of 50 allows for 50 IMAP and 50 POP3 connections at the same
+        time for a single user.
+      '';
+    };
+
     localDnsResolver = mkOption {
       type = types.bool;
       default = true;
diff --git a/mail-server/dovecot.nix b/mail-server/dovecot.nix
index 26a8002..4294a2d 100644
--- a/mail-server/dovecot.nix
+++ b/mail-server/dovecot.nix
@@ -67,6 +67,14 @@ in
           verbose_ssl = yes
         ''}
 
+        protocol imap {
+          mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
+        }
+
+        protocol pop3 {
+          mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
+        }
+
         mail_access_groups = ${vmailGroupName}
         ssl = required
         ${lib.optionalString (dovecotVersion.major == 2 && dovecotVersion.minor >= 3) ''