Describes the Syslog message format for Firewall logs with an example.

IETF Syslog Message Format (RFC 3164)

<%PRI%>%timegenerated% %HOSTNAME% %syslogtag%%msg

The following is a sample syslog message.

<158>Dec 17 07:21:16 b1-edge1 velocloud.sdwan: ACTION=VCF Deny SEGMENT=0 IN="IFNAME" PROTO=ICMP SRC=x.x.x.x DST=x.x.x.x TYPE=8 FW_POLICY_NAME=test SEGMENT_NAME=Global Segment
The message has the following parts:
  • Priority - Facility * 8 + Severity (local3 & info) - 158
  • Date - Dec 17
  • Time - 07:21:16
  • Host Name - b1-edge1
  • Syslog Tag - velocloud.sdwan
  • Message - ACTION=VCF Deny SEGMENT=0 IN="IFNAME" PROTO=ICMP SRC=x.x.x.x DST=x.x.x.x TYPE=8 FW_POLICY_NAME=test SEGMENT_NAME=Global Segment
VMware supports the following Firewall log messages:
  • With Stateful Firewall enabled:
    • Open - The traffic flow session has started.
    • Close - The traffic flow session has ended due to session timeout or the session is flushed through the Orchestrator.
    • Deny - If the session matches the Deny rule, the Deny log message will appear and the packet will be dropped. In the case TCP, Reset will be sent to the Source.
    • Update - For all the ongoing sessions, the Update log message will appear if the firewall rule is either added or modified through Orchestrator.
  • With Stateful Firewall deactivated:
    • Allow
    • Deny
Table 1. Firewall Log Message Fields
Field Description
SID The unique identification number applied to each session.
SVLAN The VLAN ID of the Source device.
DVLAN The VLAN ID of the Destination device.
IN The name of the interface on which the first packet of the session was received. In the case of overlay received packets, this field will contain VPN. For any other packets (received through underlay), this field will display the name of the interface in the edge.
PROTO The type of IP protocol used by the session. The possible values are TCP, UDP, GRE, ESP, and ICMP.
SRC The source IP address of the session in dotted decimal notation.
DST The destination IP address of the session in dotted decimal notation.
Type The type of ICMP message.
Note: The Type parameter appears in logs only for ICMP packets.
Some important ICMP types which are widely used include:
  • Echo Reply (0)
  • Echo Request (8)
  • Redirect (5)
  • Destination Unreachable (3)
  • Traceroute (30)
  • Time Exceeded (11)

For complete list of ICMP message types, see ICMP Parameters Types.
SPT The source port number of the session. This field is applicable only if the underlaying transport is UDP/TCP.
DPT The destination port number of the session. This field is applicable only if the underlaying transport is UDP/TCP.
FW_POLICY_NAME The name of the firewall policy applied to the session.
SEGMENT_NAME The name of the segment to which the session belongs to.
DEST_NAME The name of the remote-end device of the session. The possible values are:
  • CSS-Backhaul - For traffic which is destined to Cloud Security Service from edge.
  • Internet-via-<egress-iface-name> - For Cloud traffic going directly from edge using business policy.
  • Internet-BH-via-<backhaul hub name> - For Cloud-bound traffic going to Internet through Backhaul hub using business policy.
  • <Remote edge name>-via-Hub - For VPN traffic flowing through Hub.
  • <Remote edge name>-via-DE2E - For VPN traffic flowing between the edges through direct VCMP tunnel.
  • <Remote edge name>-via-Gateway - For VPN traffic flowing through Cloud gateway.
  • NVS-via-<gateway name> - For Non SD-WAN Destination traffic flowing through Cloud gateway.
  • Internet-via-<gateway name> - For Internet traffic flowing through Cloud gateway.
NAT_SRC The source IP address used for source netting the direct Internet traffic.
NAT_SPT The source port used for patting the direct Internet traffic.
APPLICATION The Application name to which the session was classified by DPI Engine. This field is available only for Close log messages.
BYTES_SENT The amount of data sent in bytes in the session. This field is available only for Close log messages.
BYTES_RECEIVED The amount of data received in bytes in the session. This field is available only for Close log messages.
DURATION_SECS The duration for which the session has been active. This field is available only for Close log messages.
REASON The reason for closure or denial of the session. The possible values are:
  • State Violation
  • Reset
  • Purged
  • Aged-out
  • Fin-Received
  • RST-Received
  • Error
This field is available for Close and Deny log messages.