> Source: [sk184977](https://support.checkpoint.com/results/sk/sk184977)

# sk184977 - Unable to authenticate with TACACS+ users via Captive Portal 

| Property | Value |
|----------|-------|
| Solution ID | sk184977 |
| Date Created | 2026-06-02 |
| Last Modified | 2026-06-07 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Symptoms

- * End users fail to authenticate using Captive Portal when traffic uses the TACACS+ protocol. By default, TACACS+ uses TCP port 49.
* On the CLI of the Policy Decision Point (PDP) Gateway, output of `pdp debug set all all` is similar to this example:

  ```
  
  [UNIQUE EVENT IDENTIFIER NUMBER]@GW[20 Feb 10:00] [TRACKER]: #27 -> OUTGOING -> PORTAL_RESPONSE -> hello ok...ip: 192.[XYZ].10.1 ,session: [SESSION ID NUMBER]
  [UNIQUE EVENT IDENTIFIER NUMBER]@GW[20 Feb 10:01] [TRACKER]: #28 -> INCOMING -> PORTAL_REQUEST -> login_auth for session: [SESSION ID], user: [USER ID NUMBER]
  check_caller_thread_safe: [WARNING] Non thread safe action: Mainloop thread id = 4041083712 while current thread id = 4015840064 (LWP 16549)
  Backtrace with 10 levels:
  [1] 0xf66357f3 [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0xf7f3)
  [2] T_event_set_socket_e [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0x12c70)
  [3] 0xf66431c6 [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0x1d1c6)
  [4] fwasync_make_connection_e_bindopt_ex [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0x1d3b0)
  [5] fwasync_connect_e_bindopt_ex [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0x1e020)
  [6] fwasync_connect_bindopt_ex [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0x1e260)
  [7] fwasync_connect_bindopt [/opt/CPshrd-R82/lib/libComUtils.so] (offset 0x1e2c0)
  [8] tacacs_plus_query [/opt/CPshrd-R82/lib/libcpauth.so] (offset 0x5f210)
  [9] fwtacacs_login_attempt [/opt/CPshrd-R82/lib/libcpauth.so] (offset 0x5b510)
  ```

## Cause

The PDPD (Policy Decision Point Daemon) process is multi-threaded. The PDPD process does not schedule TACACS+ authentication attempts in the correct thread, causing the attempts to fail.

## Solution

This solution requires authentication. Please log in to view the full solution.

---

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