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Problem with URL Filtering

Hello everyone!!

I have a problem accessing a certain GitHub URL. For example, when I try to update Pi-hole the address objects.githubusercontent.com cannot be resolved:
At first, I thought it was an issue with Pi-hole itself or with openDNS, its upstream DNS server. But I realized that this is not the case, it happens to me when I try to download something from GitHub.

Investigating, I have seen that, for example:
- If I temporarily disable the blocking, the Pi-hole blocking still does not resolve the URL.
- If I ping from outside my LAN, it does respond:
In Pi-hole I have put the URL on a whitelist. In Sophos, I have tried to do the same, I think I have done it right, but the address is still not resolved.

Any suggestions?
Kind regards,
Albert


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[edited by: Raphael Alganes at 3:26 PM (GMT -7) on 24 Oct 2024]
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  • Hello!! Slight smile

    After going around in circles, doing many tests and trying various configurations both on the Pi-hole and on the Sophos, it is clear to me that there is something in the firewall that is blocking the domain (and the subdomains) *.githubusercontent.com.
    The last test that confirms this is the ping from Sophos itself to the domain, as you can see in the screenshot, this time I do get a response:

    As I said, I have done several tests, such as adding the domain as an exception, fine-tuning the web filtering policy, fine-tuning the internet browsing policy, adding the FQDN as an exception, changing the DNS offered by the DHCP... But nothing works, I am quite confused... 

    What else could I try?

    Kind regards!! Smile

    Albert.

  • Hello!! Smiley

    Finally I've resolved the issue:

    The culprit was a third-party threat feed, the CiberHost_UK, the domain .githubusercontent.com is categorized as malware:

    Kind regards.

    Albert

  • thx for sharing your solution.

    I am wondering because I have two sfos instances and networks which also using a pihole setup. On both updates are working without any issues.

    Have reported that false-positive to sophos yet?

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