Diagnosing Network Issues

Network Diagnostics helps admins verify that the license server is reachable on the expected IP/host and port, and quickly identify common network/config issues (wrong endpoint, wrong bind/interface, DNS problems, local firewall blocking).

When run, it collects:

Network snapshot

• Local IPv4 addresses detected on the server
• (Optional) DNS resolution for the "advertised host/IP" Connection tests (TCP connect)
• localhost:<port>
• 127.0.0.1:<port> (if loopback included)
• <each local IPv4>:<port>
• (Optional) <advertised host/IP>:<port> Hints
• Simple conclusions derived from the test results (e.g. "bound to loopback only", "possible firewall block", "DNS failed").

Inputs

You’ll be asked:

Advertised host/IP (optional)

• Enter the exact address your clients are using (e.g. licenseserver.company.lan or 10.10.0.12).
• Leave blank if you only want local checks.

The port is taken from the server’s current config/status.

Output

You’ll see:

Network Snapshot

• Generated time (UTC)
• Port
• Local IPv4 list

Test Matrix Each row shows:

• Target (host:port)
• Outcome (Ok, Refused, Timeout, DnsFailed, Unreachable, Error)
• Latency (when available)
• Detail (error/diagnostic text)

Hints

• Short, actionable messages derived from the test results.

Interpreting outcomes

• Ok: Server could open a TCP connection to that target/port. If localhost is OK but NIC IPs are not, you are likely bound to loopback only.
• Refused: The OS responded immediately: nothing is listening at that target/port. Usually means server isn’t listening on that port/interface (wrong port, wrong bind address, server not running).
• Timeout: No response within the timeout window. Common causes: firewall/AV, network ACLs, wrong routing, host not reachable, or port silently dropped.
• DnsFailed: Hostname couldn’t be resolved to an IP. DNS misconfiguration, wrong hostname, missing record, or wrong DNS server.
• Unreachable: The network stack reports no route / host unreachable. Routing issue, disconnected network, invalid IP, or target is on a different network without route.
• Error: Misc failure (socket or system-level). Check the "Detail" column.

Common scenarios

• localhost OK, 127.0.0.1 OK, but all NIC IPs fail/timeout/refused
  • Likely bound to loopback.
  • Fix: bind listener to 0.0.0.0:<port> or the correct NIC IP.
• Everything is Refused
  • Server likely not listening on the configured port.
  • Fix: confirm the server is running, confirm configured port, check port conflicts.
• Everything is Timeout
  • Strong signal of firewall/AV blocking inbound, or the wrong port is being used.
  • Fix: open inbound firewall rule for the port; confirm port matches what clients use.
• Advertised host shows DnsFailed
  • Clients using a hostname will fail too.
  • Fix: correct DNS record or change clients to use a valid IP/hostname.
• Advertised host resolves, but connect fails while local NIC connect succeeds
  • Often indicates clients are using the wrong route/segment (NAT/VPN split) or the hostname points to the wrong IP.
  • Fix: correct DNS target IP; ensure advertised endpoint is reachable from the client network.

Recommended usage pattern

When troubleshooting a client report:

1. Run Network diagnostics with the advertised host/IP the client is using.
2. Confirm at least one of:
   • Advertised endpoint test is Ok
   • A NIC IP test is Ok and that IP is what clients should use
3. If not OK, follow the Hints section and rerun after changes.

Notes

• The tool performs only safe, targeted connect tests (no scanning).
• Results reflect server-side perspective. If the server can connect to itself but clients still fail, you likely have a network boundary issue (client-side firewall, routing, VLAN ACLs). In that case, use a minimal client probe tool (recommended separately) from the client machine.