Palo alto certificate error?

[Chivas]

hi all,

I am using PA-850 and configure certificate decryption. I am having the problem with this. when I configured to decrypt for any source, client would get the error "ERR_SSL_VERSION_OR_CIPHER_MISMATCH", and could not access to any websites. 

But when I configured to decrypt some client only in source, it worked well.  I dont know if It was overload at certficate decrypton. please help to advise me on this. I have about 600 users.

thanks

[BPry]

@Chivas,

You'll have to provide a bit more information on your end to get a meaningful recommendation. The PA-850 supports a max concurrent session limit for decryption of 19,200, so you could possibly be running into that depending on your setup but not with that error message. 

Can you post how you have your decryption profile setup, and how exactly you had configured the decryption policy. 

[Chivas]

Hi BPry,

I am using defaut decryption profile like below picture

and the policy is:

from source: Any -- to -- Destination: Untrust. Option: Decrypt. Type: SSL Forward Proxy.  Decryption profile: Default

The session count: about 23.200/196606

and when I use "show session all filter ssl-decrypt yes count yes" it displays 3329

Thanks

[BPry]

@Chivas,

So if you're using the default decryption profile the end client should still be able to access most sites. You may have to install the certificate that you're using to decrypt the traffic to get pass security warnings presented by the browser about not being a trusted website, but it shouldn't prevent you from accessing the site. 

Can you verify on your security policies that you don't have anything blocking the traffic? When you setup decryption you'll start to see web-browsing come across on tcp/443, make sure that you're allowing this traffic to actually pass in your security rulebase. By default this doesn't fall under 'application-default' and some people miss it when setting up decryption for the first time. 

[Chivas]

hi BPry,

Yes. I installed the certificate on clients. and allow any source to access internet. 

If I disable the dcryption policy or add some clients in to source address, clients could access internet without any errors.

but if I add "any" in source, all clients will get the error when access internet.

it worked normally for some weeks ago. just happen recenty two days.

[Raido_Rattameister]

Are users using Chrome?

Does it work with IE?

Are you using latest 8.1.4 PANOS?

[Chivas]

hi Raido,

It doesn't work with chrome, firefox, IE,...

I am using 8.0.2 PANOS. I will update Pan OS and try to see if it works.

[hpatel11]

Were you able to resolve this issue? 

[hpatel11]

I have similar issue where I'm getting "ERR_SSL_VERSION_OR_CIPHER_MISMATCH" while decrypting inbound traffic. I'm doing it for single user. 

[kiwi]

Hi @hpatel11 ,

Sounds like you're hitting an unsupported cipher.

Do a PCAP and check the client and server hello's and negotiation and match them against the compatibility matrix.

Check out this KB:

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000PMaTCAW

and check the compatibility matrix matching your PAN-OS:

https://docs.paloaltonetworks.com/compatibility-matrix/supported-cipher-suites

Cheers !

-Kiwi.