Make some scalability corrections

roles/ensure_dovecot/templates/Fedora/43/etc/dovecot/conf.d/local.conf

@@ -48,6 +48,7 @@ protocol lmtp {
 }
 
 protocol imap {
+  mail_max_userip_connections = 100
   mail_plugins {
     imap_quota = yes
   }
@@ -81,3 +82,17 @@ protocol submission {
   mail_max_userip_connections = 10
 }
 
+# --- Scalability & Memory Tuning (1 vCPU, 1GB RAM) ---
+# Safe limits to prevent OOM errors while accommodating concurrent connections
+default_process_limit = 150
+default_client_limit = 1000
+
+# --- Enhanced Diagnostic Logging ---
+# Provides detailed information about authentication and connection drops
+auth_verbose = yes
+auth_debug = yes
+mail_debug = yes
+
+# Delay failed authentication attempts by 2 seconds to slow brute force
+auth_failure_delay = 2 secs
+disable_plaintext_auth = yes

roles/ensure_dovecot/templates/Fedora/44/etc/dovecot/conf.d/local.conf

@@ -48,6 +48,7 @@ protocol lmtp {
 }
 
 protocol imap {
+  mail_max_userip_connections = 100
   mail_plugins {
     imap_quota = yes
   }
@@ -81,3 +82,17 @@ protocol submission {
   mail_max_userip_connections = 10
 }
 
+# --- Scalability & Memory Tuning (1 vCPU, 1GB RAM) ---
+# Safe limits to prevent OOM errors while accommodating concurrent connections
+default_process_limit = 150
+default_client_limit = 1000
+
+# --- Enhanced Diagnostic Logging ---
+# Provides detailed information about authentication and connection drops
+auth_verbose = yes
+auth_debug = yes
+mail_debug = yes
+
+# Delay failed authentication attempts by 2 seconds to slow brute force
+auth_failure_delay = 2 secs
+disable_plaintext_auth = yes