FortiGate
FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
wmichael
Staff
Staff
Article Id 382792
Description This article describes how to debug RADIUS CoA on FortiGate with an example of log messages for Disconnect-ACK and Disconnect-NAK.
Scope FortiGate.
Solution

To debug the RADIUS CoA messages, the following commands are used:

 

diag debug console timestamp enable

diag debug app radius-das 255

diag debug enable

To disable the debug:

 

     diag debug disable

   diag debug reset

 

In response to receiving a CoA, FortiGate will reply with either a Disconnect-ACK or Disconnect-NAK. For more information about RADIUS responses, see Technical Tip: RADIUS error codes.

 

This example log message is of a Disconnect-ACK. The FortiGate received a CoA Disconnect-Request message from RADIUS-SVR 10.200.200.10 with the Attribute Value Pairs (AVPs) Framed-IP-Address, User-Name, and Event-Timestamp. The FortiGate replied with Disconnect-ACK after disconnecting the user.

 

2025-03-12 13:07:39 32628.839 2025-03-12 13:07:39 DAS: Received 48 bytes from 10.200.200.10:55302

2025-03-12 13:07:39 32628.840 2025-03-12 13:07:39 RADIUS message: code=40 (Disconnect-Request) identifier=238 length=48

2025-03-12 13:07:39    Attribute 8 (Framed-IP-Address) length=6 pos 0xa5a0f46

2025-03-12 13:07:39       Value: 192.168.200.15

2025-03-12 13:07:39    Attribute 1 (User-Name) length=16 pos 0xa5a0f4c

2025-03-12 13:07:39       Value: 'user1@example.com'

2025-03-12 13:07:39    Attribute 55 (Event-Timestamp) length=6 pos 0xa5a0f5c

2025-03-12 13:07:39       Value: 1741784857

2025-03-12 13:07:39 32628.840 2025-03-12 13:07:39 DAS: received msg with hdr_code 40

2025-03-12 13:07:39 32628.840 2025-03-12 13:07:39 DAS: No Message-Authenticator attribute found

2025-03-12 13:07:39 32628.840 2025-03-12 13:07:39 DAS: select framed_ip 192.168.200.15

2025-03-12 13:07:39 32628.841 2025-03-12 13:07:39 DAS: select user_name user1@example.com'

2025-03-12 13:07:39 32628.841 2025-03-12 13:07:39 DAS: set ipv4 shaper for user user1@example.com (192.168.200.15: max-up=0, max-down=0 from 'RADIUS-SVR'

2025-03-12 13:07:39 32628.841 2025-03-12 13:07:39 DAS: -1 sslvpn session(s) deleted.

2025-03-12 13:07:39 32628.932 2025-03-12 13:07:39 DAS: 1 auth session(s) deleted.

 

(output omitted)

 

2025-03-12 13:07:39 32628.952 2025-03-12 13:07:39 DAS: Get coa event result 2 with req_num 12

2025-03-12 13:07:41 32630.958 2025-03-12 13:07:41 DAS: Reply ACK to 10.200.200.10:55302

2025-03-12 13:07:41 32630.958 2025-03-12 13:07:41 RADIUS message: code=41 (Disconnect-ACK) identifier=238 length=44

2025-03-12 13:07:41    Attribute 55 (Event-Timestamp) length=6 pos 0xa5a2d26

2025-03-12 13:07:41       Value: 1741784859

2025-03-12 13:07:41    Attribute 80 (Message-Authenticator) length=18 pos 0xa5a2d2c

2025-03-12 13:07:41 32630.959 2025-03-12 13:07:41       Value: - hexdump(len=16):

2025-03-12 13:07:41      C6 37 CC E6 CA 99 61 DC 45 56 79 43 11 F9 84 B4   .7....a.EVyC....

 

This example log message is of a Disconnect-NAK. FortiGate received a CoA Disconnect-Request message from RADIUS-SVR 10.200.200.10 with the AVPs Framed-IP-Address, User-Name, and Event-Timestamp. There was no user auth session in this case, so FortiGate replied with Disconnect-NAK with an AVP Error-Cause Value: 503, Session Context Not Found.

For more information about CoA error codes see: RADIUS change of authorization (CoA) - FortiSwitch administration guide.

 

2025-03-12 13:10:29 32798.039 2025-03-12 13:10:29 DAS: Received 48 bytes from 10.200.200.10:53199

2025-03-12 13:10:29 32798.039 2025-03-12 13:10:29 RADIUS message: code=40 (Disconnect-Request) identifier=4 length=48

2025-03-12 13:10:29    Attribute 8 (Framed-IP-Address) length=6 pos 0xa5a17c6

2025-03-12 13:10:29       Value: 192.168.200.15

2025-03-12 13:10:29    Attribute 1 (User-Name) length=16 pos 0xa5a17cc

2025-03-12 13:10:29       Value: 'user1@example.com'

2025-03-12 13:10:29    Attribute 55 (Event-Timestamp) length=6 pos 0xa5a17dc

2025-03-12 13:10:29       Value: 1741785026

2025-03-12 13:10:29 32798.040 2025-03-12 13:10:29 DAS: received msg with hdr_code 40

2025-03-12 13:10:29 32798.040 2025-03-12 13:10:29 DAS: No Message-Authenticator attribute found

2025-03-12 13:10:29 32798.040 2025-03-12 13:10:29 DAS: select framed_ip 192.168.200.15

2025-03-12 13:10:29 32798.040 2025-03-12 13:10:29 DAS: select user_name user1@example.com

2025-03-12 13:10:29 32798.040 2025-03-12 13:10:29 DAS: set ipv4 shaper for user user1@example.com (192.168.200.15): max-up=0, max-down=0

from 'RADIUS-SVR'

2025-03-12 13:10:29 32798.040 2025-03-12 13:10:29 DAS: -1 sslvpn session(s) deleted.

2025-03-12 13:10:29 32798.041 2025-03-12 13:10:29 DAS: 0 auth session(s) deleted.

2025-03-12 13:10:29 32798.041 2025-03-12 13:10:29 DAS: No Message-Authenticator attribute found

 

(output omitted)

 

2025-03-12 13:10:29 32798.056 2025-03-12 13:10:29 DAS: Get coa event result 2 with req_num 13

2025-03-12 13:10:31 32800.068 2025-03-12 13:10:31 DAS: Reply NAK to 10.200.200.10:53199

2025-03-12 13:10:31 32800.068 2025-03-12 13:10:31 RADIUS message: code=42 (Disconnect-NAK) identifier=4 length=50

2025-03-12 13:10:31    Attribute 101 (Error-Cause) length=6 pos 0xa5a2d26

2025-03-12 13:10:31       Value: 503

2025-03-12 13:10:31    Attribute 55 (Event-Timestamp) length=6 pos 0xa5a2d2c

2025-03-12 13:10:31       Value: 1741785029

2025-03-12 13:10:31    Attribute 80 (Message-Authenticator) length=18 pos 0xa5a2d32

2025-03-12 13:10:31 32800.069 2025-03-12 13:10:31       Value: - hexdump(len=16):

2025-03-12 13:10:31      0D C7 0E 48 FD 16 57 DC F5 A8 67 18 4D CE 7E C3   ...H..W...g.M.~.

 

For more information about RADIUS AVPs and VSAs, see RADIUS AVPs and VSAs - FortiGate administration guide.

 

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