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DPI issue with AnyDesk Software

We're having an issue with anydesk beeing blocked in DPI due to invalid Certificates.

Anydesk uses own certificates, not trusted anywhere but in their software.

CN = AnyNet Root CA

CN = AnyNet Relay

Both seem to have the same fingerprint: 9e:08:d2:58:a9:02:cd:4f:e2:4a:26:b8:48:5c:43:0b:81:29:99:e3

We created a firewall rule for the users that need Anydesk, allowed HTTP/S and a custom port of Anydesk 6568

No WebFilter enabled on that FW rule, no IPS and App Control either.

Still the traffic comes to the DPI where it's blocked because of: TLS handshake fatal alert: unknown CA(48).

I don't understand why the traffic is scanned by DPI when the firewall rule has no webfiltering enabled.

I was able to install the AnyDesk Root CA to XG but not the Relay Certificate as CA which generates an error.

Certificate isn't a valid CA certificate or can't be used for signing.

This is the firewall rule 320 that hits here

and that the DPI rule

This is a packet in firewall log

2022-05-23 11:45:03Firewallmessageid="00001" log_type="Firewall" log_component="Firewall Rule" log_subtype="Allowed" status="Allow" con_duration="11" fw_rule_id="320" nat_rule_id="0" policy_type="2" user="" user_group="" web_policy_id="0" ips_policy_id="0" appfilter_policy_id="0" app_name="Anydesk" app_risk="3" app_technology="Client Server" app_category="Remote Access" vlan_id="" ether_type="Unknown (0x0000)" bridge_name="" bridge_display_name="" in_interface="lag0.13" in_display_interface="User" out_interface="lag0.2524" out_display_interface="lag0.2524" src_mac="68:84:7E:8D:A0:8A" dst_mac="C8:4F:86:FC:00:0D" src_ip="172.16.xxx.xxx" src_country="R1" dst_ip="138.199.36.117" dst_country="" protocol="TCP" src_port="52930" dst_port="443" packets_sent="7" packets_received="5" bytes_sent="544" bytes_received="2742" src_trans_ip="" src_trans_port="0" dst_trans_ip="" dst_trans_port="0" src_zone_type="LAN" src_zone="LAN" dst_zone_type="WAN" dst_zone="WAN" con_direction="" con_event="Stop" con_id="754337024" virt_con_id="" hb_status="No Heartbeat" message="" appresolvedby="EAC" app_is_cloud="0"

This is a packet in DPI log:

2022-05-23 11:44:53SSL/TLS inspectionmessageid="19018" log_type="SSL" log_component="SSL" log_subtype="Error" severity="Information" user="" src_ip="172.16.xxx.xxx" dst_ip="138.199.36.117" user_group="" src_country="R1" dst_country="" src_port="52930" dst_port="443" app_name="" app_id="0" category="IPAddress" category_id="83" con_id="754337024" rule_id="8" profile_id="3" rule_name="LAN-2-WAN" profile_name="Strict compliance" bitmask="Valid" key_type="KEY_TYPE__EC" key_param="EC secp256r1" fingerprint="9e:08:d2:58:a9:02:cd:4f:e2:4a:26:b8:48:5c:43:0b:81:29:99:e3" resumed="0" cert_chain_served="TRUE" cipher_suite="TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384" sni="138.199.36.117" tls_version="TLS1.2" reason="TLS handshake fatal alert: unknown CA(48)." exception="" message=""

What has to be done, to get this traffic out of DPI or to make XG trust the certificates?



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Parents
  • DPI and Web filter has no ties in the product. 

    DPI in general means, the traffic will be looked at and optionally decrypted. It works on all ports (443 and 1234 etc.). 

    Web Filter is only for Port 443. That is the reason, you can decrypt or Scan traffic but not doing any kind of "Web filtering" (which essentially mean, you do not want to go on certain websites). But you still can decrypt it. 

    See packet flow: community.sophos.com/.../life-of-a-packet-sophos-firewall

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Reply
  • DPI and Web filter has no ties in the product. 

    DPI in general means, the traffic will be looked at and optionally decrypted. It works on all ports (443 and 1234 etc.). 

    Web Filter is only for Port 443. That is the reason, you can decrypt or Scan traffic but not doing any kind of "Web filtering" (which essentially mean, you do not want to go on certain websites). But you still can decrypt it. 

    See packet flow: community.sophos.com/.../life-of-a-packet-sophos-firewall

    __________________________________________________________________________________________________________________

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