Sending LTM\GTM logs to DCD devices
Hello all, I am currently working on installing four DCD's to the F5 estate I manage and am looking to export the logs from the BIG-IP's to the four DCD's using an HSL setup to load balance these between these. Reading through the following link Create a remote logging pool of DCDs (and others) it is clear that different modules require different port numbers to be used for logging but is there a specific port to be used for sending logs from the LTM and GTM modules? I see no reason why this wouldn't be possible but I can't find details anywhere that specify which port should be used for these. Any pointers would be much appreciated. Thanks
HSL - Local TimeZone - in syslog server
Dear all, hope you are doing well. I have a question about the HSL timestamps which is sending by default. When we were using the standard syslog, in the log messages we had the local-timezone But, while we are swithing to HSL, it is in UTC . Apr 29 09:22:26 hostname.omitted debug tmm1[19608]: Rule <output omitted <- Standard Syslog logging Apr 29 07:22:26 hostname.omitted 29/04/2026 09:22:26 <output omitted, the Timestamp is from irule> <- HSL is it possible somehow to get as well the localtimezone, without modifying the syslog KR Peter
High Speed Logging vs Telemetry Streaming (Logging to SIEM)
My goals is to send web application traffic logs from my virtual servers to an external SIEM. It looks like there are quite a few ways to approach this, so I want to check with the community to see what works best for you. Ideally, this would be a high-volume configuration with logging enabled for 400+ public virtual servers. At a minimum, I would like to collect the client IP, user agent, URI path, virtual IP, virtual server name, pool, server name, and server-side response code. I reviewed the overview here: Getting Started with iRules: Logging & Comments | DevCentral It is clear that High Speed Logging (HSL) would be the preferred approach to ensure the resource and capacity burden is placed on the TMM (data plane) and not the control/management plane and to avoid writing to disk on the F5 BIG-IP host. I could write to syslog servers and forward these logs to my SIEM. The HSL seems to be straight forward to configure with a sample iRule looking like: when CLIENT_ACCEPTED { set vs [IP::local_addr]:[TCP::local_port] # Open HSL connections with configured pools set hsl_pool_1 [HSL::open -proto UDP -pool Pool_Syslog_1] set hsl_pool_2 [HSL::open -proto UDP -pool Pool_Syslog_2] } when SERVER_CONNECTED { set client [IP::client_addr]:[TCP::client_port] set srv [IP::remote_addr]:[TCP::remote_port] set log_message "<134>Client: $client connected to $vs and routed to server $srv at [clock format [clock seconds] -format \"%Y-%m-%d %H:%M:%S\"]" # Send logs to both HSL pools HSL::send $hsl_pool_1 $log_message HSL::send $hsl_pool_2 $log_message } However, when I searched through the DevCentral forums for references to SIEM logging, I found that most examples used Telemetry Streaming and AS3 for configuration. An official KB can be found here: Configure Azure sentinel or other telemetry consumer integration with BIG-IP and there is a f5devcentral github publication with configuration declarations for this approach for multiple SIEM vendors (e.g., analytics-vendor-dashboards/elastic at main · f5devcentral/analytics-vendor-dashboards for Elastic) For a use case like mine that involves high-volume logging in BIG-IP, do you know if HSL or Telemetry Streaming would be best to minimize the impact on BIG-IP?Any approach to encrypting HSL traffic such that no plain text is ever sniffable?
Hi - we have been asked to integrate a vendor logging solution on our F5s that uses HSL to send information about requests to and responses from our HTTP/HTTPS VIPs on our LTMs. (I describe this configuration in more detail in a post yesterday, with the title "Pool used with HSL::open - what are the requirements? Any way to make it send using TLS?" ... but in summary, they use an iRule with HSL:open against a manually created pool, that uses as members an HTTP VIP created on the same F5; that in turn requires us to use a static route to send the traffic over the management interface, so it can reach the VIP on the same F5). Though we have a solution for the flow (see other post), it results in the logged content being plain-text on our network, whilst going from the management port to the VIP used as a destination of the HSL pool. Is there any general solution or design that would permit us to send out HSL logging such that it is TLS encrypted right from the moment it is sent by the F5, never appearing in plain text on our network? Thank you!Intermediate iRules: High Speed Logging - Spray Those Log Statements!
High Speed Logging has been around since version 10.1, and has been integral to many projects over the past few years. Prior to HSL's introduction, logging remotely was configured entirely in syslog or could be handled in iRules by specifying a destination in the log statement. One enhancement with HSL to that scenario was to allow a pool of servers to be configured for a destination, so given a pool of servers, the log messages were sure to arrive somewhere (ok, for TCP they were sure to arrive!) A drawback with either the log or HSL::send command, however, is that the message was only going to hit one destination. A workaround for that problem is to just use as many commands as necessary to hit all your destinations, but that's not very efficient. Enter the publisher. Beginning in version 11.3, a new option to the HSL::open command was added that allows you to send data to a log publisher instead of only to a pool. This allows you to spray that data to as many servers as you like. In my test setup, I used alias interfaces on a linux virtual machine as the destinations, and created a pool for each to be added to the publisher: ltm pool lp1 { members { 192.168.101.20:514 { address 192.168.101.20 } } } ltm pool lp2 { members { 192.168.101.21:514 { address 192.168.101.21 } } } ltm pool lp3 { members { 192.168.101.22:514 { address 192.168.101.22 } } } Once I have the pools defined, I create the log destinations: sys log-config destination remote-high-speed-log lp1 { pool-name lp1 protocol udp } sys log-config destination remote-high-speed-log lp2 { pool-name lp2 protocol udp } sys log-config destination remote-high-speed-log lp3 { pool-name lp3 protocol udp } Finally, I create the publisher for use in the iRules: sys log-config publisher lpAll { destinations { lp1 lp2 lp3 } } That's all the background magic required to get to the iRules showing off the -publisher option in HSL::open: ltm rule testrule { when CLIENT_ACCEPTED { set lpAll [HSL::open -publisher /Common/lpAll] } when HTTP_REQUEST { HSL::send $lpAll "<190> [IP::client_addr]:[TCP::client_port]-[IP::local_addr]:[TCP::local_port]; [HTTP::host][HTTP::uri]" } } Finally, some visual evidence for the skeptics out there: You can see that all three destinations got the message, and the message arrived as formatted. So now, armed with this new option (as of version 11.3), go forth and code!
Most efficient methods for Connection logging?
Does anyone have real world experience with logging connections at a high rate? If so, which methods are you using to collect and transmit the data? We have a requirement to log all connections going through our F5 devices. Things like the client/server-side IPs/ports as well as HTTP details for HTTP VIPs and DNS details from our GTMs. It's the Whitehouse M-21-31 mandate if anyone if familiar with it. I've used Request Logging Profiles and various iRules with HSL to collect this type of data before, but I've never been too concerned about overhead because I would only apply them as needed, like when t-shooting an issue with a VIP. Our busiest appliance pushes around 150k conn/sec and 5k HTTP req/sec, so I now have consider the most efficient methods to avoid any kind of impact to traffic flows. I've done some lab testing with several different methods but I can't do any meaningful load tests in that environment. Below are some of my opinions based on my lab testing so far. Data Collection AVR - I like that this single feature can meet all the requirements for collecting TCP, HTTP, and DNS data. It would also be relatively easy to perform audits to ensure the VIPs have the necessary Analytics profiles as we can manage it from the AVR profiles themselves. My main concern is the overhead that results from the traffic analysis. I assume it has to maintain a large database where it stores all the analyzed data even if we just ship it off to Splunk. Even the data shipped off to Splunk includes several different logs for each connection (each with a different 'Entity'). Request Logging Profile - This is fairly flexible and should have low overhead since the F5 doesn't need to analyze any of the data like AVR does. This only collects HTTP data so we still need another solution to collect details for non HTTP VIPs. It would be a pain to audit since we don't have use any kind of deployment templates or automation. iRule - This provides a lot of flexibility and it is capable of collecting all the necessary data, but I don't know how well performance overhead compares to AVR. This would also be a pain to audit due to lack of deployment templates and automation. Data Transmission HSL UDP Syslog - I imagine this is the most efficient method to send events, but it's likely only a matter of time before we are required to use TCP/TLS. Telemetry Streaming - This is the more modern method and it offers some interesting features like System Poller, which could eventually allow us to move away from SNMP polling. We would need a workaround for our GTM-only devices because they cannot run a TS listener.
Device Fingerprinting for mobile devices
We have published Microsoft Exchange server behind ASM+APM policies. I am using BotDefense to generate Device IDs for the connecting clients and then inserting the value of "device_id" variable into HTTP header and then passing it to APM. APM extracts the "device_id" value from HTTP header and sets it as an APM variable: ACCESS::session data set "session.custom.device_id" "$device_id" This APM session variable is then called in APM iRules to perform the required logic. So far, the logic and traffic flow is working as expected. Now, here comes the problem part: If the client is not a web browser, the whole logic fails because BotDefense is generating Device IDs based on JavaScript challenge. In case of Microsoft Exchange, the client could be a mobile device using the native email app of the phone (not mobile browser) like the mail app of Andriod or iOS devices. How can we perform device fingerprinting and generate Device IDs in such case? All mobile devices use the standard Exchange protocol "Microsoft ActiveSync" which is based on HTTPS. When traffic hits my virtual server from a mobile client, BIG-IP can detect it and differentiate it from other web browser traffic because all requests coming from mobile devices have this particular URI string in the HTTP Request: "/Microsoft-Server-ActiveSync". But because it is not a web browser, the JavaScript challenge is not performed and no Device ID generated. My question is: How can we perform fingerprinting and generate Device IDs for mobile devices (not mobile browsers)? Here is my ASM iRule which is handling the Device IDs and fingerprinting: ============================================================================================================================== when RULE_INIT { set static::TPS_Value 1 set static::debug 1 # set as 1 - send request logs set 0 if no request logs should be sent. set static::PBD_debug 1 # list of botdefense actions you want to get request log on set static::Logged_PBD_actions "tcp_rst browser_challenge internal_bigip_response captcha_challenge" set static::host_header "Host: webmail.company.com" } when HTTP_REQUEST { set hsl [HSL::open -proto TCP -pool ASM_Log_Pool2] set http_request [HTTP::request] #HSL::send $hsl $http_request } when BOTDEFENSE_REQUEST { #for demo purpose, make the challange valid from the first request - make sure you go to the default if {[HTTP::uri] equals "/"} { BOTDEFENSE::cs_allowed true } #Mandate the device_id attribute extraction BOTDEFENSE::cs_attribute device_id enable } when BOTDEFENSE_ACTION { set device_id [BOTDEFENSE::device_id] if {$static::debug > 0} {log "reason is, [BOTDEFENSE::reason], action is [BOTDEFENSE::action], botdefense device_id is: $device_id"} if {$static::Logged_PBD_actions contains [BOTDEFENSE::action]} { set botdefense_action [BOTDEFENSE::action] set botdefense_reason [BOTDEFENSE::reason] set PBD_header [concat Host: webmail.company.com\r\nPbd_Action: $botdefense_action\r\nPbd_reason: $botdefense_reason] set asm_http_requet_log [string map -nocase [list $static::host_header $PBD_header] $http_request] if {($static::PBD_debug > 0) && ([info exists asm_http_requet_log])} { HSL::send $hsl $asm_http_requet_log } } log "action is [BOTDEFENSE::action], reason is: [BOTDEFENSE::reason] cs_allowed is: [BOTDEFENSE::cs_allowed]" if {([BOTDEFENSE::action] eq "tcp_rst") && [BOTDEFENSE::cs_allowed] eq 0} { set res [BOTDEFENSE::action custom_response { sorry i am blocking you, try to restart the session } 200] if {$res eq "ok"} { set botdefense_responded 1 } } # if {[BOTDEFENSE::action] eq "captcha_challenge"} { # set res [BOTDEFENSE::action allow] # log "captcha challange with res $res" # if {$res eq "ok"} { # log "bypass allow" # } # } #} when ASM_REQUEST_DONE { if {$static::debug > 0} {log "http uri is [HTTP::uri]"} virtual Hackazone_APM_virt } when HTTP_REQUEST_SEND { clientside { # Need to force the host header replacement and HTTP:: commands into the clientside context # as the HTTP_REQUEST_SEND event is in the serverside context if {$static::debug > 0} {log "device id is: $device_id"} HTTP::header insert "device_id" "$device_id" # if { $suspicious_browser eq "1" } { # HTTP::header insert "suspicious_browser" "1" # log "sending suspicious_browser header" # } # log "after the change [HTTP::request]" } } when HTTP_RESPONSE_RELEASE { if {[info exists botdefense_responded]} { HTTP::header insert "X-TS-BP-Action" "2" } } =================================================================================================================================== Many thanks.
alertd high cpu usage
Hello, So we tried taxing the HSL logging of our 12.1.2 cluster with several (4) simple while true; do curl http://virtual-ip/; done curl loops. The virtual IP had a simple iRule that logged [HTTP::request] several times. Our logging is BSD syslog to HSL, to a logstash pool. During our testing, we saw alertd rising to 100% CPU and maxing out there. CPU usage on the dashboard increased aswell, as you see in the image below. sys log-config destination remote-high-speed-log elk-hsl-destination { pool-name syslog-pool } sys log-config destination remote-syslog rsyslog-to-hsl-elk { remote-high-speed-log elk-hsl-destination } sys log-config filter elk-hsl-filter { level info publisher elk-hsl-publisher } sys log-config publisher elk-hsl-publisher { destinations { rsyslog-to-hsl-elk { } } } Any idea how we can combat this? We would like to use HSL to reduce CPU consumption, but this seems like a lot of fuss for simple logging. Ideas? Thanks!HSL logging logs strange URI
Hi! Wrote a logging iRule to log cache response headers with HSL. It works fine generally but some uris are pretty strange. Here is the rule: when HTTP_REQUEST priority 999 { set host [string tolower [HTTP::host]] set uri [HTTP::uri] set hsl [HSL::open -proto UDP -pool syslog-514_pool] } when HTTP_RESPONSE { if { [HTTP::header exists "Cache-Control"] } { set CacheControl [HTTP::header "Cache-Control"] } else { set CacheControl " " } if { [HTTP::header exists "Expires"] } { set Expires [HTTP::header "Expires"] } else { set Expires " " } HSL::send $hsl "[string map [list "\t \t" "\t-\t"]\ "<165>\t\ $Expires\t\ $CacheControl\t\ $uri\t\ $host\t\ "]\n" } Here is one of the lines that looks strange (note that this particular response did not have an Expires header): Date Log Level Source IP Expires Max-Age URI Host 2014-04-11 08:08:36Local4.Notice10.0.0.1max-age=60, must-revalidate, publichttps://ourwebsite.com/directory/service.svc?query=stringourwebsite.com We can't seen the strange URI's in the IIS logs. Could it be that the BigIP rejects it because the request is malformed? I am out of ideas. /Patrik
