title: Squid is giving me 403 from time to time
body: <p>I have a squid server that is used by a lots of collage.</p>
  
  <p>This is the squid config:</p>
  
  <pre><code>dns_v4_first on
  
  # ACL Squid
  external_acl_type is_user ipv4 ttl=600 negative_ttl=10 children-max=2000 %SRC /opt/acl_squid.py
  
  # ACL PROXY Access
  acl is_real_user external is_user
  
  #acl SSL method CONNECT
  acl SSL_ports port 443
  acl Safe_ports port 80      # http
  #acl Safe_ports port 21      # ftp
  acl Safe_ports port 443     # https
  #acl Safe_ports port 70      # gopher
  #acl Safe_ports port 210     # wais
  acl Safe_ports port 1025-65535  # unregistered ports
  #acl Safe_ports port 280     # http-mgmt
  #acl Safe_ports port 488     # gss-http
  #acl Safe_ports port 591     # filemaker
  #acl Safe_ports port 777     # multiling http
  acl SSL method CONNECT
  acl CONNECT method CONNECT
  acl to_ipv6 dst ipv6 # Enable IPv6
  
  http_access deny !Safe_ports
  
  # ACL Allow Host/Domain
  http_access allow is_real_user
  http_access deny !Safe_ports
  http_access allow localhost
  http_access deny all
  
  # Enable IPv6
  #tcp_outgoing_address ipv6_address to_ipv6
  # Port
  http_port 0.0.0.0:3128
  coredump_dir /var/spool/squid
  
  
  refresh_pattern ^ftp:           1440    20%     10080
  refresh_pattern ^gopher:        1440    0%      1440
  refresh_pattern -i (/cgi-bin/|\?) 0     0%      0
  refresh_pattern (Release|Packages(.gz)*)$      0       20%     2880
  refresh_pattern .               0       20%     4320
  
  # Chache Off
  cache deny all
  
  # Performance tuning
  maximum_object_size 1 MB
  maximum_object_size_in_memory 128 KB
  cache_mem 64 MB
  quick_abort_min 1024 KB
  quick_abort_max 2048 KB
  quick_abort_pct 90
  pipeline_prefetch on
  shutdown_lifetime 1 second
  
  # Log
  access_log syslog:local3.info squid
  </code></pre>
  
  <p>The external ACL is just checking the request IP to be sure that has access to that proxy (its checking via API to a DB to see if the IP exists there).</p>
  
  <p>The issue is that from time to time (not only me, lots of collage) I'm receiving 403 (access denied) for no reason.</p>
  
  <p>Could you please let me know what exactly I can do in order to have access all the time with no interruption?</p>
  
  <p>What I do when I'm receiving 403 is to restart the squid server and the everything is back to normal.</p>
  
  <p>Regards,
  Ciprian</p>