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ESP Logs

1 Introduction

This Technical Note provides supplementary information about the Edge Security Pack (ESP) logs in the Kemp LoadMaster. For further information on ESP in general, refer to the ESP Feature Description on the Kemp Documentation Page.

2 ESP SSO Debug Logs

ESP SSO debug logs are extensive. The primary purpose of these logs is to provide deep insight into processing and developer-level debugging information. While these logs are not documented, they are verbose in nature. They can be examined for information and parsed where necessary.

These logs are debug level and are disabled by default under normal operating conditions.

Generally, these logs are only enabled in collaboration with Kemp Customer Support personnel, to provide assistance with troubleshooting problematic flows.

3 ESP Extended Logs

These logs are generated from the L7 layer of the LoadMaster system. They provide insight into ESP and security-related events on the system. The format of these logs rarely change, unless there is a specific request to add extra information (which typically would be new data at the end of the string).

Three identifiers are used:


These map to the corresponding files on the system:

  • /var/log/userlog/connection
  • /var/log/userlog/user
  • /var/log/userlog/security

For more information on each of the log types, refer to the sections below.

3.1 Connection Logs

The connection logs provide information relating to the client, Virtual Service, Real Server, and the nature of the connection (if SSL is in use or not).



SSL accept on "VSIP:Port" from "Client IP:Port"



Connect from "ClientIP:Port" to "RSIP:Port" using "VSIP:Port"

3.2 User Logs

User logs reflect the activity of the user. The logs have the following format.



"VSIP:Port" ("RSIP:Port") User "USERNAME" requested|attempted "HTTP METHOD" "URI" "USERAGENT"


USERNAME reflects the user

The log indicates what the user requested OR attempted

HTTP METHOD reflects the HTTP method used, for example, GET or POST

URI comprises of http or https, the host being accessed, and the path and query as presented

USERAGENT is the User Agent header from the HTTP request (if enabled to be included). To enable this, go to System Configuration > Miscellaneous Options > L7 Configuration in the LoadMaster Web User Interface (WUI) and tick the Include User Agent Header in User Logs check box.


The user logs also explicitly shows log off activity.



"VSIP:Port": User "USERNAME" logged off



For common activity events (for example, log on and access denied), or if a dialogue is required between the client and LoadMaster (for example, for two-factor authentication), the user logs capture this detail in a simple user log message.



"VSIP:Port": User "USERNAME" "MESSAGE" from "HOST"

Where the MESSAGE can be:

  • logged on
  • denied access
  • blocked access
  • requires passphrase
  • requires re-enter passphrase
  • requires pin
  • requires re-enter pin
  • requires password reset


You can also generate user logs in Common Event Format (CEF). CEF is an open log management standard that improves the interoperability of security-related information from different security and network devices and applications.


To enable the CEF log format, go to System Configuration > Miscellaneous Options > L7 Configuration and select the Use CEF Log Format check box. CEF log format is easily consumable for Security Information and Event Management (SIEM) tools, such as; Splunk, SolarWinds, LogRhythm, AlienVault, and so on.

The CEF logs are composed of a header and an extension. The header is well defined within the specification and the extension is a key-value pair vendor specific segment. The following log headers appear in the user logs when the CEF format is enabled:

  • vs
  • event type
  • source ip
  • source port
  • user
  • user agent
  • request method
  • request url

For example:

CEF:0|Kemp|LM|1.0|14|Request|1|vs= event=Request srcip= srcport=54548 method=GET url= useragent=Mozilla/5.0

In LoadMaster firmware version 7.2.51, ESP user logs were expanded to be more useful and applicable to enterprise customers with extensive logging infrastructure. User Authentication, Authorization, and Accounting (AAA) information is included in the logs, including the time of request, username, domain, AAA server, AAA protocol type, AAA result, and error message.

To view, clear, and save the ESP user logs, go to System Configuration > Logging Options > Extended Log Files in the LoadMaster WUI.

Here is an example of these logs:

2021-09-08T07:34:22-04:00 lb100 ssomgr: vs= server= protocol=LDAP Unencrypted result=0:Success


2021-09-08T08:08:40-04:00 lb100 ssomgr: vs= domain=KPAUTO.NET msg=Deleted expired user session, start time:1631102854 duration:66 seconds

You can generate these logs in Common Event Format (CEF) by enabling the Use CEF Log Format check box in System Configuration > Miscellaneous Options > L7 Configuration. Here is an example of these CEF logs:

2021-09-08T07:17:15-04:00 lb100 ssomgr: CEF:0|Kemp|LM|1.0|100|User AAA|0|vs= event=User AAA server= protocol=LDAP Unencrypted result=0:Success


2021-09-08T07:32:22-04:00 lb100 ssomgr: CEF:0|Kemp|LM|1.0|101|User session timeout|0|vs= event=User session timeout domain=KPAUTO.NET msg=Deleted expired user session, start time:1631099835 duration:906 seconds

4 Security Logs

These logs are generated when configuration on the LoadMaster prevents access to a service, or the LoadMaster detects something malicious regarding the request.



Attempted XSS attack on "VSIP:Port" from "ClientIP:Port" (dtcode "INTERNAL DETECTION CODE")



Blocked access to invalid "TARGET" "HOST" from "ClientIP:Port" to "VSIP:Port"\n


  • TARGET is the directory or host
  • HOST is the host information from HTTP request or [No host specified]



Blocked SMTP access to "MAIL ADDRESS" from "ClientIP:Port" to "VSIP:Port"

SMTP parse failure of data from "ClientIP:Port" to "VSIP:Port"

Last Updated Date

This document was last updated on 21 February 2022.

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