If the
Application Command Center (ACC) on
your firewall indicates a GTP problem that you want to troubleshoot,
select and look for the GTP packet
capture icon (
![](/content/dam/techdocs/en_US/dita/_graphics/11-1/gtp/gtp_pcap_icon.png/jcr:content/renditions/original)
) at the beginning
of rows that capture troublesome GTP packets. In those rows you’ll
see the GTP Event Type (such as Abnormal GTPv2-C message with missing
mandatory IE), the Subscriber Identity (IMSI), source and destination
IP address of the packet, and other information.