The proxy worked at home. Why does it fail on a VPS?
You move a working application from your laptop to a VPS. The proxy hostname, port and code stay the same, but access stops working. If the endpoint uses IP authentication, check the address arriving at the proxy before changing the application. The allowlist checks the incoming connection The provider compares your connection's public source IP with an allowed list. This is the address of the…
A proxy setup functions well on a personal computer but encounters issues when migrated to a Virtual Private Server (VPS). Despite keeping the hostname, port, and code consistent, the proxy no longer accepts connections. This problem may originate from the proxy's source IP address not matching entries on the allowlist.
To troubleshoot, initially confirm the VPS uses IP authentication. If so, ascertain the correct outbound address from the machine hosting the application. This step necessitates checking the route used to reach the proxy, accounting for potential gateways like NAT, VPNs, or container hosts that could alter the public source IP.
It is crucial to consider the address family, such as IPv4 or IPv6, ensuring the allowlist entry aligns with the family being used. Direct checks may not reveal the source IP seen by the proxy on the incoming connection, which is particularly relevant when using the proxy for destination-facing access.
Furthermore, public source IPs can change over time, especially on home connections or cloud workloads. While automatic updates to the allowlist can be beneficial, their effectiveness depends on the provider's support and the reliability of the update process. For applications with frequently changing sources, employing username/password authentication may be more practical, contingent on the product's support for this method.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
