====== Squid - Alerts - SURICATA UDPv4 invalid checksum ======

Disable Hardware Checksum Offloading under **System -> Advanced -> Networking**.

{{:squid:alerts:pfsense_-_system_-_advanced_-_networking_-_network_interfaces.png?800|}}

----

===== Suppress Rules =====

<code bash>
# Messes up with DNS resolution on LAN.
1:2200073 # SURICATA IPv4 invalid checksum

# Bittorrent noise, DNS.
1:2200075 # SURICATA UDPv4 invalid checksum
1:2200078 # SURICATA UDPv6 invalid checksum

# Lots of useless noise.
1:2200076 # SURICATA ICMPv4 invalid checksum
1:2200079 # SURICATA ICMPv6 invalid checksum
</code>

----

<WRAP info>
**NOTE:**  Try toggling the **Hardware Checksum Offloading**.

If that does not do it, you can simply disable that particular rule by either clicking the red X icon on the **Alerts** tab in the GID/SID column, or you can find and selectively disable that rule on the **Rules** tab for the interface.

See this thread from the official Suricata documentation Wiki for details:

  * http://suricata.readthedocs.io/en/latest/performance/packet-capture.html.

Suricata uses PCAP for packet capture during Legacy Blocking Mode operation, and Netmap for Inline IPS Mode operation.

In both cases, hardware checksum offloading needs to be disabled.
</WRAP>