Important note about SSL VPN compatibility for 20.0 MR1 with EoL SFOS versions and UTM9 OS. Learn more in the release notes.

how to diagnose Heartbeat SSL errors in heartbeatd.log - or why do they occur all the time?

Heartbeat is always a bit tricky here.

As we have several rules with block clients with no HB, the impact off technical heartbeat issues is always high.

Endpoints have the latest official Client versions from Central. Currently 2024.2.3.4.0

For years, the heartbeatd.log on the firewall is always full of SSL errors.

The most frequent error is

Incoming connection from 10.xxx.xxx.xxx failed. SSL error:

Incoming connection from 172.xxx.xxx.xxx failed. SSL error:

The IP ranges are directly connected and routed by the XGS. IP 10 is SSL VPN, 172 is LAN.

We have 5-10 per minute of them.

During SSL handshake the Firewall answers with a encrypted alert.

The Clients sends a RST packet during SSL handshake after Server Hello.

hb log:

[2024-09-24 08:11:28.752Z] WARN HBSession.cpp[26394]:344 bufferDisconnectEvent - Incoming connection from 10.yyy.yyy.131 failed. SSL error:
[2024-09-24 08:11:29.436Z] WARN HBSession.cpp[26394]:344 bufferDisconnectEvent - Incoming connection from 10.yyy.yyy.131 failed. SSL error:
[2024-09-24 08:11:33.624Z] WARN HBSession.cpp[26394]:344 bufferDisconnectEvent - Incoming connection from 10.yyy.yyy.131 failed. SSL error

tcpdump taken on FW:

filter for client IP and TLS

99100	2024-09-24 10:11:28,724384	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99109	2024-09-24 10:11:28,752450	10.yyy.yyy.131	52.5.76.173	TLSv1.2	768	Application Data, Application Data, Application Data
99111	2024-09-24 10:11:28,752605	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99144	2024-09-24 10:11:28,831272	10.yyy.yyy.131	52.5.76.173	TLSv1.2	207	Client Hello
99150	2024-09-24 10:11:28,831711	52.5.76.173	10.yyy.yyy.131	TLSv1.2	1422	Server Hello
99167	2024-09-24 10:11:28,850463	52.5.76.173	10.yyy.yyy.131	TLSv1.2	1171	Certificate, Server Key Exchange, Certificate Request, Server Hello Done
99195	2024-09-24 10:11:28,896512	10.yyy.yyy.131	52.5.76.173	TLSv1.2	1092	Certificate
99223	2024-09-24 10:11:28,967032	10.yyy.yyy.131	52.5.76.173	TLSv1.2	451	Client Key Exchange, Certificate Verify, Change Cipher Spec, Encrypted Handshake Message
99225	2024-09-24 10:11:28,967313	52.5.76.173	10.yyy.yyy.131	TLSv1.2	107	Change Cipher Spec, Encrypted Handshake Message
99261	2024-09-24 10:11:29,015035	10.yyy.yyy.131	52.5.76.173	TLSv1.2	115	Application Data
99262	2024-09-24 10:11:29,015078	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99286	2024-09-24 10:11:29,043512	10.yyy.yyy.131	52.5.76.173	TLSv1.2	1052	Application Data, Application Data
99287	2024-09-24 10:11:29,043758	52.5.76.173	10.yyy.yyy.131	TLSv1.2	136	Application Data
99289	2024-09-24 10:11:29,063528	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99290	2024-09-24 10:11:29,063532	10.yyy.yyy.131	52.5.76.173	TLSv1.2	93	Application Data
99355	2024-09-24 10:11:29,137979	10.yyy.yyy.131	52.5.76.173	TLSv1.2	301	Application Data
99357	2024-09-24 10:11:29,138049	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99594	2024-09-24 10:11:29,416737	10.yyy.yyy.131	52.5.76.173	TLSv1.2	294	Application Data
99595	2024-09-24 10:11:29,416921	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99602	2024-09-24 10:11:29,427061	10.yyy.yyy.131	52.5.76.173	TLSv1.2	294	Application Data
99603	2024-09-24 10:11:29,427198	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99692	2024-09-24 10:11:29,536222	10.yyy.yyy.131	52.5.76.173	TLSv1.2	207	Client Hello
99694	2024-09-24 10:11:29,536401	52.5.76.173	10.yyy.yyy.131	TLSv1.2	1422	Server Hello
99715	2024-09-24 10:11:29,565157	52.5.76.173	10.yyy.yyy.131	TLSv1.2	1171	Certificate, Server Key Exchange, Certificate Request, Server Hello Done
99768	2024-09-24 10:11:29,648546	10.yyy.yyy.131	52.5.76.173	TLSv1.2	1092	Certificate
99839	2024-09-24 10:11:29,714316	10.yyy.yyy.131	52.5.76.173	TLSv1.2	451	Client Key Exchange, Certificate Verify, Change Cipher Spec, Encrypted Handshake Message
99841	2024-09-24 10:11:29,714571	52.5.76.173	10.yyy.yyy.131	TLSv1.2	107	Change Cipher Spec, Encrypted Handshake Message
99893	2024-09-24 10:11:29,784144	10.yyy.yyy.131	52.5.76.173	TLSv1.2	115	Application Data
99894	2024-09-24 10:11:29,784206	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99902	2024-09-24 10:11:29,803184	10.yyy.yyy.131	52.5.76.173	TLSv1.2	1052	Application Data, Application Data
99903	2024-09-24 10:11:29,803383	52.5.76.173	10.yyy.yyy.131	TLSv1.2	136	Application Data
99906	2024-09-24 10:11:29,822811	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
99907	2024-09-24 10:11:29,822834	10.yyy.yyy.131	52.5.76.173	TLSv1.2	93	Application Data
102253	2024-09-24 10:11:33,552360	10.yyy.yyy.131	52.5.76.173	TLSv1.2	294	Application Data
102255	2024-09-24 10:11:33,552468	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
102283	2024-09-24 10:11:33,624670	52.5.76.173	10.yyy.yyy.131	TLSv1.2	87	Encrypted Alert
102301	2024-09-24 10:11:33,643726	10.yyy.yyy.131	52.5.76.173	TLSv1.2	207	Client Hello
102303	2024-09-24 10:11:33,643910	52.5.76.173	10.yyy.yyy.131	TLSv1.2	1422	Server Hello
102311	2024-09-24 10:11:33,672658	52.5.76.173	10.yyy.yyy.131	TLSv1.2	1171	Certificate, Server Key Exchange, Certificate Request, Server Hello Done
102335	2024-09-24 10:11:33,744687	10.yyy.yyy.131	52.5.76.173	TLSv1.2	1092	Certificate
102373	2024-09-24 10:11:33,806659	10.yyy.yyy.131	52.5.76.173	TLSv1.2	451	Client Key Exchange, Certificate Verify, Change Cipher Spec, Encrypted Handshake Message
102375	2024-09-24 10:11:33,806957	52.5.76.173	10.yyy.yyy.131	TLSv1.2	107	Change Cipher Spec, Encrypted Handshake Message
102437	2024-09-24 10:11:33,896198	10.yyy.yyy.131	52.5.76.173	TLSv1.2	115	Application Data
102438	2024-09-24 10:11:33,896244	52.5.76.173	10.yyy.yyy.131	TLSv1.2	93	Application Data
...
197843	2024-09-24 10:14:18,918870	10.yyy.yyy.131	52.5.76.173	TLSv1.2	97	Application Data
205073	2024-09-24 10:14:33,917076	10.yyy.yyy.131	52.5.76.173	TLSv1.2	97	Application Data

full dump available

one other is SSL error: SSL routines:ssl3_read_bytes sslv3 alert certificate expired

 - as far as I know from the past this is due to the client caching old HB certificates and uses them, when connecting. When it recognizes, it has expired, it uses the next one in the HB cert store and has success.

SFOS 20.0.1



Edited TAGs
[edited by: Erick Jan at 9:35 AM (GMT -7) on 24 Sep 2024]