Sophos UTM Client VPN Error (Authenticate/Decrypt packet error: packet HMAC authentication failed)

Hi mbrehm,

Thank you for reaching out to Sophos Community.

mbrehm said:

Wed Mar 31 08:50:18 2021 Authenticate/Decrypt packet error: packet HMAC authentication failed

It seems this event is generated by the client itself. What does openvpn.log show at the time of instance?

You may filter openvpn.log with date & time:

==> To check latest(present-day) events:

utm:/root # cat /var/log/openvpn.log | grep -i "2021:04:21"          <== Date

or 

utm:/root # cat /var/log/openvpn.log | grep -i "2021:04:21-14:"          <== Date & time

==> To check archived events:

utm:/root # zcat /var/log/openvpn/2021/04/openvpn-2021-04-20.log.gz | grep -i "2021:04:20"          <== Date

or

utm:/root # zcat /var/log/openvpn/2021/04/openvpn-2021-04-20.log.gz | grep -i "2021:04:20-16:"          <== Date & time

There is also a ticket on OpenVPN: community.openvpn.net/.../543

Hello Yash Kothari,

Thank you for your fast answer,

UTM openvpn.log looks like:

2021:03:31-08:50:18 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xxx:55323 Connection reset, restarting [-1]
2021:03:31-08:50:18 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xxx:55323 SIGUSR1[soft,connection-reset] received, client-instance restarting
2021:03:31-08:50:18 sophos01-2 openvpn[12381]: id="2202" severity="info" sys="SecureNet" sub="vpn" event="Connection terminated" username="adm_os" variant="ssl" srcip="92.206.xxx.xxx" virtual_ip="10.250.xxx.xxx" rx="16796009" tx="267233086"
2021:03:31-08:50:18 sophos01-2 openvpn[12381]: PLUGIN_CALL: POST /usr/lib/openvpn/plugins/openvpn-plugin-utm.so/PLUGIN_CLIENT_DISCONNECT status=0
2021:03:31-08:50:34 sophos01-2 openvpn[12381]: TCP connection established with [AF_INET]92.206.xxx.xxx:62032 (via [AF_INET]80.208.xxx.xxx:443)
2021:03:31-08:50:35 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 TLS: Initial packet from [AF_INET]92.296.xxx.xx:62032 (via [AF_INET]80.208.xxx.xxx:443), sid=c2a869bd 3a0aea57
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 VERIFY OK: depth=0, C=de, L=, O=, CN=ADM
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 VERIFY OK: depth=1, C=de, L=, O=
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 VERIFY OK: depth=1, C=de, L=, O=
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 VERIFY OK: depth=0, C=de, L=, O=
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 PLUGIN_CALL: POST /usr/lib/openvpn/plugins/openvpn-plugin-utm.so/PLUGIN_AUTH_USER_PASS_VERIFY status=2
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 TLS: Username/Password authentication deferred for username 'adm_os' [CN SET]
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 Data Channel Encrypt: Cipher 'AES-128-CBC' initialized with 128 bit key
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 Data Channel Decrypt: Cipher 'AES-128-CBC' initialized with 128 bit key
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 DHE-RSA-AES256-GCM-SHA384, 2048 bit RSA
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 [adm_os] Peer Connection Initiated with [AF_INET]92.296.xxx.xx:62032 (via [AF_INET]80.208.xxx.xxx:443)
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 TLS Error: local/remote TLS keys are out of sync: [AF_INET]92.206.xxx.xx:62032 (via [AF_INET]80.208.xxx.xxx:443) [0]
2021:03:31-08:50:36 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 TLS Error: local/remote TLS keys are out of sync: [AF_INET]92.206.xxx.xx:62032 (via [AF_INET]80.208.xxx.xxx:443) [0]
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: 92.206.xxx.xx:62032 TLS Error: local/remote TLS keys are out of sync: [AF_INET]92.206.xxx.xx:62032 (via [AF_INET]80.208.xxx.xxx:443) [0]
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 OPTIONS IMPORT: reading client specific options from: /etc/openvpn/conf.d/adm_os
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 MULTI_sva: pool returned IPv4=10.250.xxx.xxx, IPv6=(Not enabled)
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: id="2201" severity="info" sys="SecureNet" sub="vpn" event="Connection started" username="adm_os" variant="ssl" srcip="92.206.xxx.xx" virtual_ip="10.250.xxx.xxx"
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 PLUGIN_CALL: POST /usr/lib/openvpn/plugins/openvpn-plugin-utm.so/PLUGIN_CLIENT_CONNECT status=0
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 OPTIONS IMPORT: reading client specific options from: /tmp/openvpn_cc_00c2cb5f631d4fff21fa1ea4dc958e69.tmp
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 MULTI: Learn: 10.250.xxx.xxx -> adm_os/92.206.xxx.xx:62032
2021:03:31-08:50:37 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 MULTI: primary virtual IP for adm_os/92.206.xxx.xx:62032: 10.250.xxx.xxx
2021:03:31-08:50:38 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 PUSH: Received control message: 'PUSH_REQUEST'
2021:03:31-08:50:38 sophos01-2 openvpn[12381]: adm_os/92.206.xxx.xx:62032 send_push_reply(): safe_cap=940

Hello,

still got this problem. Any Ideas to fix this?

Hi mbrehm

Just a question. Do all the users have the problem to sign in or only some of those? Is it dependend on the client or client version they are using?

Hi mbrehm

Just a question. Do all the users have the problem to sign in or only some of those? Is it dependend on the client or client version they are using?

Hello ThomW,

There is no problem to sign in at all. 
The problem is that the VPN Client unseres bekomm 3 to 6 times a Disconnect a Day. 
I tried different Versions of the client but nothing changed