Trisul Probe Configuration File

All configuration parameters for each Trisul Probe is stored in a single XML main configuration file called trisulProbeConfig.xml. This file is found on all Trisul-Probe nodes.

Location: /usr/local/etc/trisul-probe/domain0/probe0/context0/trisulProbeConfig.xml

for context named data1 the path would be …probe0/context_data1/trisulProbeConfig.xml

Root privileges needed to edit
Also see trisulHubConfig.xml for editing Hub node parameters


Click on a section to see the config parameters inside that section.
Section What part of trisul does it configure
App The trisul running process
Logging Logging policy – file sizes and rotation
Ring Full content storage and retention policy
Reassembly TCP reassembly and advanced metering
File Extraction Configure File Extraction
IDS Alerts Unix sockets for accepting Unified and Unified2 alerts
Offline Import For importing large pcap dumps (mostly used for testing
Tuning Tuning packet processing pipeline
Edges Options related to the Graph Analytics


Settings for the Trisul daemon process

Commonly modified parameters are Setuid, TrisulMode, LicenseFile
Parameters Defaults Description
User trisul.trisul Which user/group should trisul run as after dropping root privileges.
TempFolder /tmp
DBRoot /usr/local/var/lib/trisul-probe/domain0/probe0/context0 The base directory under which Trisul stores all its data.
UsageRedMark Generate an alert when disk usage on this probe node cross this percent value. Leave blank or set to 0 to disable disk usage alerts
ConfigDB /usr/local/var/lib/trisul-probe/domain0/probe0/context0/ config/TRISULCONFIG.SQDB Location of the configuration database.
PluginsLibDirectory /usr/local/lib/trisul/plugins Where trisul looks for dynamic (called so) plugins
PluginsConfDirectory /usr/local/etc/trisul-probe/domain0/probe0/context0 Where trisul looks for additional configuration files and server certificates (for TRP).
PluginsDataDirectory /usr/local/share/trisul/plugins Where trisul looks for plugin configuration data.
ProbeID SE-LINK A mnemonic to identify this instance of Trisul, this string is reported via TRP.
ProbeDesc Trisul Probe monitors the S-E link traffic only A short description of this instance of trisul.
RunStateDirectory /usr/local/var/lib/trisul-probe/domain0/probe0/context0/run Volatile data for current run stored here
PluginsDataDirectory /usr/local/share/trisul-probe/plugins Plugins store data here; eg from downloaded feeds
PidFile /usr/local/var/run/ File where trisul stores the process id of the current running instance.
TrisulMode TAP This determines whether you run Trisul in raw packets mode or Netflow mode.TAP Processes all raw packets from the selected network adapters.NETFLOW_TAP Processes Netflow packets
ValidTrisulModes TAP,NETFLOW_TAP Unused – just a hint for the previous parameter.
LicenseFile /usr/local/etc/trisul-probe/LicenseKey.txt Location of the license file.
ReportsDirectory ../reports The directory where DDoS reports are stored in Netflow mode


Configures logging and rotation of the probe process trisul

Parameters Defaults Description
Logdir /usr/local/var/log/trisul Where the log files are stored.
Logfile ns-???.log Log file pattern. The default is ns-001.log, ns-002.log, etc.
Loglevel DEBUG All messages higher than this level are logged. The available log levels in order of severity (most severe one first is).
DEBUG — Recommended default level
LogRotateSize 5000000 Size of each log file is allowed to grow to this size before Trisul moves to the next file.
LogRotateCount 5 The number of files in the log ring, oldest files will be rotated.


Full content storage policy.

The Ring section allows you to control.

  • How big each full content file gets
  • How many such full content files are in a slice
  • How many slices in operational, reference, and archive areas
  • Passphrase file (the content files are AES-128 CTR mode encrypted)
  • Flow rules for content trimming
Parameters Defaults Description
Enabled True Setting this to False will disable all options below, full content will not be saved.
BaseDir /usr/local/var/lib/
Parent directory under which full content files are saved.
Encryption AES-128-CTR The encryption cipher. Currently supported modes are AES-128-CTR and NONE. Specify NONE to disable encryption of raw packet storage.
PassphraseFile /usr/local/etc/
The encryption passphrase for the full content files.
FilePrefix RCF_ Content files are called RCF_001.triscap, RCF_001.triscap, etc.. This options allows you to change the RCF_ part.
FileSizeMB 100 Size of each full content file in megabytes.
Maximum allowed value = 8000 (8GB). If you specify a size greater than this limit, Trisul will ignore it and use 8GB as the value.
SyncSeconds 60 Diagnostic use only.
SysStatsUpdateSecs 2 Diagnostic use only.
EnableDDosNetflowTapTrail Set this to TRUE to enable the DDoS Ring mechanism.
DefaultMode FULL To cut down on full content data, Trisul allows you to apply a variety of policies. The supported modes are
FULL Everything is saved This is the default mode
FLOWCAP10M Only first 10MB of each TCP flow is saved.
FLOWCAP1M Only first 1MB of each TCP flow is saved.
FLOWCAP100K Only first 100KB of each TCP flow is saved.
FLOWCAP10K Only first 10KB of each TCP flow is saved.
HEADERS Only headers are saved, typically upto the TCP/UDP layer
IGNORE Nothing is saved
RuleChain Each packet is evaluated against a rule chain, which is a list of rules.


Controls how much of raw packet data is stored. There are three areas oper, ref, and archive The packet slices are always written in oper then slide into ref , archive, and then deleted as specified by the SlicePolicy below.

SliceCount 32 Number of operational slices. The size of each slices is fixed as specified by FileSizeKB parameter
SliceCount 32 Number of reference slices. Setting this to zero will move slices straight to the archive.
SliceCount 0 Number of archive slices. If you set this to 0, slices move directly to /dev/null (ie are deleted).

Rule Chain

Rule chains are used to control full packet storage policies.

If you desire even more fine grained control of packet storage policy on a per-flow basis see the Packet Storage LUA Script type
  • Each rule is an expression in the Trisul filter format
  • Treatment of each packet is one of : Store full packet, Store header, or Ignore
  • The first rule to match determines the treatment given to the packet
  • If no rule matches, the treatment specified in the DefaultMode parameter is applied

Rule mode=“FULL

If present, packets which match this rule get stored completely.

Rule mode=“FLOWCAP10M”

If present,

  • packets which match this rule and
  • belong to a flow which has transferred less than 10MB bidirectionally get stored fully.

Rule mode=“FLOWCAP1M”

If present,

  • packets which match this rule and
  • belong to a flow which has transferred less than 1MB bidirectionally get stored fully.

Rule mode=“FLOWCAP100K”

If present,

  • packets which match this rule and
  • belong to a flow which has transferred less than 100KB bidirectionally get stored fully.

Rule mode=“FLOWCAP10K”

If present,

  • packets which match this rule and
  • belong to a flow which has transferred less than 10KB bidirectionally get stored fully.

Rule mode=“HEADERS

If present, packets which match get only their headers stored. The headers include at least the Ethernet/IP/TCP/UDP layers.

Rule mode=“IGNORE

If present, packets which match get ignored (sent to /dev/null).


Specifies how many files you want to keep in each of the three areas. The size of each file is capped by the FileSizeKB parameter.

You want this policy :

  • Each Slice file is 1GB
  • Store 20GB in the operational area (maybe you have limited SSD or RAID5)
  • Store 500GB in the reference area
  • Store 1TB in the archive

Then the SliceCounts will be 20,500,1000 for the operational,ref, archive areas.


Controls how Trisul handles IP fragmentation and TCP reassembly.


Parameters Defaults Description
Enabled MetricsOnly Reassembles IP fragments. This is disabled by default due to the CPU and Mem load it can place on Trisul on busy links. The values are
Full IP reassembly is enabled. Use this on light links or if you suspect IP fragmentation on busy links
Do not perform reassembly but collect metrics about fragmentation in the Aggregates counter group under the key ipfrag. This is the default option
Completely disable IP Defragmentation. Simply ignore IP fragments. Use this on busy links
HiWater 1000 Hi water mark for number of simultaneous fragment chains to track.
LoWater 500 Lo water mark for number of simultaneous fragment chains. If the number of fragments crosses the HiWater mark, Trisul gets rid of the LRU least-recently-used items and prunes it to the LoWater mark.


Flow tracking keeps track of how much data has been transmitted in either direction in a single TCP flow.

  • Required for flow based full content storage policy (like storing first 1M of each flow)
  • Required for TCP Reassembly
  • Required for all reassembly based applications like XFF Deproxy, URI Log, Content Type meters, etc
Parameters Defaults Description
Enabled True True or False values.
HiWater 8000 Hi water mark for number of simultaneous flows that can be tracked. If the number of simultaneous active flows exceeds the high water mark, Trisul will prune the oldest active flows until the number of flows goes one below the low water mark.
LoWater 6000 Lo water mark for TCP flow pruning. See explanation for HiWater.


Controls TCP Reassembly.

  • Required for all reassembly based applications like XFF Deproxy, URI Log
  • Required for reassembly based meters like HTTP Content Types, HTTP Hosts, URL Filter, etc
Parameters Defaults Description
Enabled True True or False values
MaxBytes 0
KickoffBytes 5000 Some meter within Trisul must express an interest in reassembled data for a given flow before this limit is reached. Otherwise reassembly is stopped at this point for this flow.
Ports Traffic on these ports are reassembled. By default Trisul this is "" because uses heuristics to detect applications independent of port. You can override this behaviour by setting to a string like 3000,80,443,22,21 to reassemble only these ports
Direction INOUT Options

Only the IN direction; direction of first SYN+ACK is reassembled

Only the OUT direction; direction of initial SYN is reassembled

Both directions are reassembled


Some advanced applications.

Since these applications depend on the TCP Reassembly feature, they are resistant to TCP fragmentation evasions.

Parameters Defaults Description
EnableXFFDeproxy True Useful in a corporate environment with web proxies. If set to true, Trisul can deproxy web traffic by looking at the X-Forwarded-For HTTP header. The actual IP is substituted for all metering and flow analysis instead of the proxy’s IP.
EnableURILog True Logs all HTTP URLs requested. These URLS show up as Resources in Trisul where they are correlated and made searchable.
EnableHostMeter True Add traffic metering by HTTP Host header. The net effect of enabling this is that the HTTP Host counter group is made active.
EnableContentTypeMeter True Add traffic metering by HTTP Content-Type header. Activates the HTTP Content Type counter group.
EnableSSLCertLog True Logs all SSL certificate chains
EnableHTTPFTS True Full Text Search (FTS) enabled for all HTTP Headers seen
EnableSSLFTS True FTS enabled for all SSL Certificates seen
MaxHTTPFTSPerFlow Currently unused
EnableFTPTrack True Tracks FTP data session by matching the corresponding control flows
EnableSSLRecordExtraction False If you want access to the raw TLS Protocol PDUs. If set to “True” ; Trisul will generate “TLS:RECORD” callbacks you can hook on to in the Reassembly engine. Unless you are working deep with TLS you typically can leave this as False.

File Extraction

Controls the HTTP file extraction feature.

Needs tmpfs partition : If you enable File Extraction you also need to create a special in-memory TMPFS partition (also known as RAMFS partition). Quickest way to create this is to use trisulctl_probe createramfs probe0 default A 100MB partition would suffice for loads < 1Gbps. For more read File Extraction LUA API in detail
Parameters Defaults Description
Enabled False Feature is enabled or not
RamFsDir ProbeRoot/tmp/ramfs The directory mounted on the TMPFS file system
AutoDelete True The tmpfs file system is automatically cleaned as the files are processed by the LUA script framework. Set this to False for debugging purpose only or if you take control of deleting the filesystem from your LUA scripts
ChunkSizeMB 5 For large files your LUA script will be handed chunks of this size. Tweak this based on how much RAM you can allocate to the tmpfs filesystem


Controls how security alerts from Snort/Barnyard2 are handled

Parameters Defaults Description
Enabled True Enables this feature
SnortUnixSocket /tmp/snort_alert Trisul opens this unix socket and listens for alerts. The default socket name is snort_alert for Unified events from Snort, and barnyard2_alert for Unified2 events from Barnyard2. The directory name is passed to snort or barnyard2 via the -l parameter

Multiple sockets : You can add any number of <SnortUnixSocket> elements to listen to multiple sockets at once.
GenerateDDosReport Set this to TRUE to trigger Trisul Probe to generate a DDoS report on certain TCA firing.
DDosReportTopCount 100 By default 100 top items are included in the DDoS report
DDosReportWindow>PastSeconds 120 By default, include in the report 2 minutes prior to the DDoS attack trigger
DDosReportWindow>FutureSeconds 60 By default, include in the report 1 minutes after the DDoS attack trigger


Controls aspects of PCAP file import.

Parameters Defaults Description
LoopCount 1 Used for testing. Runs the same capture file/directory this many time past Trisul. Each run is appended time-wise to the end of the previous run. This is used internally by us to generate months of data from a few days of capture by repeating them over and over.
AppendMode TRUE Appends the run to the previous runs time-wise. The packet time stamps in the capture file are offset by the last time of the previous run.
InterfileGapSecs 60 When importing multiple files, this option puts a gap of this many seconds between each file. There is no purpose of this option other than to view a gap in the charts representing the capture files.
AutoSortByCaptime TRUE When TRUE, the candidate capture files are sorted by time order (earliest to latest), and then imported into Trisul. When FALSE, the files and subdirectories are processed in alphabetical order.
ResumeStalledImport FALSE Dependency:AutoSortByCaptime must be TRUE
Treats the import as a resumption of a previously stalled or aborted offline import. When TRUE, Trisul will first determine what timestamp was last flushed. Then it will skip all packets earlier than that timestamp and continue importing when newer timestamps are seen.
This feature is used to resume a stopped import without reprocessing everything again.
Use this feature with the following caution :
# Due to the discontinuous nature, some packets may be missed or double counted around the timestamp where the earlier import was aborted
# Flows may be duplicated around the time
AddEthernetFCS FALSE If set to true, will add 12 bytes to every ethernet packet to account for FCS


Fine tune the packet processing pipeline for peak performance.

Parameters Defaults Description
AnalysisQueueCapacity 1000000 Queue size for frontend packet stream to backend analytics stream
PcapQueueCapacity 5000 Queue for disk packet storage
FeedbackQueueCapacity 1000000 Queue size of backend to frontend (reverse/feedback) stream
PcapRAIDStripeSize 1048576 Sequential writes of this size.
GrainSize 64 Number of packets to process in a batch. You can increase this value if you have a CPU with a large L1/L2 cache. If the entire batch fits in cache memory – it can increase concurrency – and decrease drops.
SpongeWindow 1 A key internal data structure parameter to help with multicore.
Number of seconds a single core must accumulate before synchronizing. In most cases, leave this alone.
InflightTokens 2 Number of work items in parallel. Maps to number of hardware threads you want to give to trisul.
TCPReassFilters 2 Number of TCP Filters – Trisul will hash and load share. Typically matches the number of InflightTokens
CoreAffinityNet CPU cores you want you pin the packet processing threads to. Use “1,2,4” to pin to CPU Cores 1,2,4
CoreAffinityRAID CPU cores allowed to do disk writes for packet storage
CoreAffinityAnalysis Currently unused
FBQDrainChunkSize -1 Controls how fast an internal data structure called the Feedback Queue is drained
FlowMemcapPolicy FLEXIBLE Determines how Trisul copes under severe load. This can happen on a very busy network or under a DDoS attack against Trisul itself or elsewhere on the network. Trisul detects this condition when Hi Water marks are crossed for counters or flows.
The available options are :
FLEXIBLE Trisul is not too rigid about the Hi Water mark, it allows usage to grow beyond the high water mark within the streaming window (1-minute)
FIXED When a Hi Water mark is hit, no new counters are flows are accepted. Existing ones are metered as usual. At the next flush interval, the counters or flows are pruned down to the low water mark and things proceed as usual
StreamingWindowMSecs 60000 The streaming window in milliseconds. The default value is 1 minute. Do not change this unless you have a very good reason
DisableFlowTupleFeedback false Flow tuple feedback is a feature in Trisul that allows you to measure per-IP and per-APP connection metrics. This can be overkill for some environments like ISP’s who deal with millions of flows/sec. Disable this in those environemts. We also suggest disabling this option when the FeedbackQueue (FBQ) sees pressure leading to spiky IP and App flow connection metrics.
MaxTCARangeAlerts 100 When using TCA range alerts (see TCA generate only these many alerts. The reason we need a safety cap on this feature is an incorrect configuration with a TCA range can result in uncontrolled alerts (eg when any IP crosses 1Kbps). For safety we have chosen a cap or 100


Controls the streaming graph analytics part of Trisul

Parameters Defaults Description
Enabled True Enables this feature
EnableFlowEdges True Do you want edge vertex data to be generated for every flow? For very large networks, consider disabling this option.