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Bug #79767 Firewall rules on appear to be blocking source port 1024
Submitted: 2020-07-01 19:01 UTC Modified: 2020-07-01 21:14 UTC
Avg. Score:4.5 ± 0.5
Reproduced:4 of 4 (100.0%)
Same Version:3 (75.0%)
Same OS:4 (100.0%)
From: chkimes at github dot com Assigned:
Status: Open Package: Systems problem
PHP Version: Irrelevant OS: Any
Private report: No CVE-ID: None
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 [2020-07-01 19:01 UTC] chkimes at github dot com
1024 is not a reserved port, but many misconfigured firewall rules tend to include it and block outbound connections that use it as a source port. This is causing connection failures from Azure VMs, where the outbound load balancer often starts assigning ports from 1024 upward.

Test script:
From any fresh Azure VM *without a public IP assigned*:


Did your web server firewall rules recently change?


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 [2020-07-01 21:14 UTC]
-Package: Website problem +Package: Systems problem
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Last updated: Mon Aug 03 21:01:24 2020 UTC