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Description
Description
Hello, we've been running into various hostname/dns related issues on Windows and macOS for the last few weeks. This one is for Windows specifically.
The FQDN (as reported by Python) is unreachable.
hostname = socket.gethostname()
fqdn = socket.getfqdn()Hostname: runnervmk2jw4
Ping to hostname runnervmk2jw4: successful
IP addresses for runnervmk2jw4:
10.1.0.105
fe80::3e59:29d0:86a2:da4a
fe80::cce:3a6f:9359:9b32
172.20.80.1
Pinging IP addresses for runnervmk2jw4:
Ping to 10.1.0.105: successful
Ping to fe80::3e59:29d0:86a2:da4a: successful
Ping to fe80::cce:3a6f:9359:9b32: successful
Ping to 172.20.80.1: successful
==================================================
FQDN: runnervmk2jw4.askkogcowbeexaxaijjtd4dtkg.cx.internal.cloudapp.net
Ping to fqdn runnervmk2jw4.askkogcowbeexaxaijjtd4dtkg.cx.internal.cloudapp.net: failed
IP addresses for runnervmk2jw4.askkogcowbeexaxaijjtd4dtkg.cx.internal.cloudapp.net:
10.1.0.103
Pinging IP addresses for runnervmk2jw4.askkogcowbeexaxaijjtd4dtkg.cx.internal.cloudapp.net:
Ping to 10.1.0.103: failed
As you can see the FQDN does not resolve to an ip address associated with the Windows runner.
Run from my test repo here: https://github.com/externl/sandbox/actions/runs/16176086721/job/45661454665
Platforms affected
- Azure DevOps
- GitHub Actions - Standard Runners
- GitHub Actions - Larger Runners
Runner images affected
- Ubuntu 22.04
- Ubuntu 24.04
- macOS 13
- macOS 13 Arm64
- macOS 14
- macOS 14 Arm64
- macOS 15
- macOS 15 Arm64
- Windows Server 2019
- Windows Server 2022
- Windows Server 2025
Image version and build link
Runner Image
Image: windows-2022
Version: 20250701.1.0
Included Software: https://github.com/actions/runner-images/blob/win22/20250701.1/images/windows/Windows2022-Readme.md
Image Release: https://github.com/actions/runner-images/releases/tag/win22%2F20250701.1
Is it regression?
Yes, this used to work.
Expected behavior
FQDN should resolve to an IP associated with runner.
Actual behavior
FQDN resolves to IP not associated with runner.
Repro steps
Get fqdn on Windows using Python and try to ping it.
socket.getfqdn()You can also use this script I threw together:
#!/usr/bin/env python3
import socket
import platform
import subprocess
import sys
def get_ips_for_hostname(hostname):
"""Get all IP addresses associated with the hostname."""
try:
# Get both IPv4 and IPv6 addresses
addrinfo = socket.getaddrinfo(hostname, None)
# Extract unique IP addresses
ip_addresses = set()
for addr in addrinfo:
ip = addr[4][0]
ip_addresses.add(ip)
return list(ip_addresses)
except socket.gaierror:
return []
def ping_target(target):
"""
Ping a target (hostname or IP) and return whether it was successful.
Args:
target (str): The hostname or IP address to ping
Returns:
bool: True if ping was successful, False otherwise
"""
# Adjust ping command based on operating system
param = "-n" if platform.system().lower() == "windows" else "-c"
command = ["ping", param, "1", target]
try:
result = subprocess.run(
command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True
)
return result.returncode == 0
except Exception as e:
print(f"Error pinging {target}: {e}")
return False
def run_checks_for_target(target_name, target_value):
"""Run all checks for a given target (hostname or FQDN).
Returns:
bool: True if all checks passed, False if any failed
"""
print(f"{target_name}: {target_value}")
has_failures = False
# Ping the target directly
ping_success = ping_target(target_value)
ping_status = "successful" if ping_success else "failed"
print(f"Ping to {target_name.lower()} {target_value}: {ping_status}")
if not ping_success:
has_failures = True
print()
# Get IPs for the target
ips = get_ips_for_hostname(target_value)
if not ips:
print(f"No IP addresses found for {target_value}")
return False
print(f"IP addresses for {target_value}:")
for ip in ips:
print(f" {ip}")
# Ping each IP
print(f"\nPinging IP addresses for {target_value}:")
for ip in ips:
success = ping_target(ip)
status = "successful" if success else "failed"
print(f" Ping to {ip}: {status}")
if not success:
has_failures = True
return not has_failures
def main():
# Get hostname and FQDN
hostname = socket.gethostname()
fqdn = socket.getfqdn()
all_passed = True
# Run checks for hostname
hostname_passed = run_checks_for_target("Hostname", hostname)
if not hostname_passed:
all_passed = False
print("\n" + "=" * 50 + "\n")
# Run checks for FQDN (only if different from hostname)
if fqdn != hostname:
fqdn_passed = run_checks_for_target("FQDN", fqdn)
if not fqdn_passed:
all_passed = False
else:
print(f"FQDN is the same as hostname: {fqdn}")
# Exit with appropriate status code
if not all_passed:
print("\nSome checks failed. Exiting with status code 1.")
sys.exit(1)
else:
print("\nAll checks passed.")
sys.exit(0)
if __name__ == "__main__":
main()