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# Which Problems Are Solved
A customer reached out that after an upgrade, actions would always fail
with the error "host is denied" when calling an external API.
This is due to a security fix
(https://github.com/zitadel/zitadel/security/advisories/GHSA-6cf5-w9h3-4rqv),
where a DNS lookup was added to check whether the host name resolves to
a denied IP or subnet.
If the lookup fails due to the internal DNS setup, the action fails as
well. Additionally, the lookup was also performed when the deny list was
empty.
# How the Problems Are Solved
- Prevent DNS lookup when deny list is empty
- Properly initiate deny list and prevent empty entries
# Additional Changes
- Log the reason for blocked address (domain, IP, subnet)
# Additional Context
- reported by a customer
- needs backport to 2.70.x, 2.71.x and 3.0.0 rc
# Which Problems Are Solved
System administrators can block hosts and IPs for HTTP calls in actions.
Using DNS, blocked IPs could be bypassed.
# How the Problems Are Solved
- Hosts are resolved (DNS lookup) to check whether their corresponding
IP is blocked.
# Additional Changes
- Added complete lookup ip address range and "unspecified" address to
the default `DenyList`
