topic Captive portal + decryption + squid: https problem. in General Topics

Captive portal + decryption + squid: https problem.

okress — Thu, 25 Aug 2016 13:19:01 GMT

Hi,

I try to configure path for users to access the Internet. I use Palo Alto and squid. But not everything works as I expected.

The path:

user---Palo Alto ---squid ---Internet.

Squid is behind Palo Alto because of citrix users. I want to control citrix users access and in scenario: user---squid---Palo Alto--Internet, it's not possible. Squid changes source ports.

Captive portal and decryption are configured.

Everything works for unknown users who reach http. User authentication by kerberos protocol succeed. If known user opens https, traffic is decrypted and website is loaded correctly with certificate from Palo Alto.

But when unknown user tries to open https Palo Alto doesn't redirect him to captive portal.

On user station wireshark shows:

user: connect website:443

PA: 200 connection established

user: Client Hello

PA: Server Hello

PA: Certificate

user: Client Key Exchange, Change Cipher Spec, Hello Request, Hello Request

PA: Change Cipher Spec, Encrypted Handshake Message

user: Application Data (GET website)

PA: sometimes ACK.

After this Palo Alto sends RST to squid and client station (Chomre shows connection reset), sometimes communication just stops (page loads into infinity)

PAN-OS 7.1.2

Tryed this with user-squid-PA-Internet, the same problem.

Any idea why this happens?

Thank you for any help.

Re: Captive portal + decryption + squid: https problem.

BPry — Thu, 25 Aug 2016 15:25:37 GMT

Out of curiosity do you actually have a captive portal profile built out?

Re: Captive portal + decryption + squid: https problem.

okress — Fri, 26 Aug 2016 06:35:25 GMT

I set up captive portal browser-challenge rule, enabled captive portal with SSL/TLS Service Profile and Authentication Profile in redirect mode, on zone enabled User Identification, on inteface set up management profile with permitted Response Pages.

I think thats all I need for captive portal.

Re: Captive portal + decryption + squid: https problem.

okress — Wed, 31 Aug 2016 08:22:13 GMT

After few tests I discoverd the problem occurs when https is tunneling. Maybe palo alto has problem with decryption and redirection when https goes via another port e.g. 8080.