Error map

Ping: Request timed out Networking: ping — Request timed out / 100% packet loss (host drops or filters ICMP)

Networking · layer 2, Network

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Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.

Ping: Request timed out — Networking: ping — Request timed out / 100% packet loss (host drops or filters ICMP) (Networking)Ping: Reque…1005 — Cloudflare Error 1005: Access denied — The owner of this website has banned the autonomous system number (ASN) your IP address is in (Cloudflare)10051006 — Cloudflare Error 1006 / 1007 / 1008: Access denied — Your IP address has been banned (Cloudflare)10061020 — Cloudflare Error 1020: Access Denied (Cloudflare)10201012 — Cloudflare Error 1012: Access denied (Cloudflare)1012iptables: No chain/target/match — driver failed programming external connectivity on endpoint: iptables: No chain/target/match by that name (Docker)iptables: No chain/…No route to host — connect: No route to host (EHOSTUNREACH) (Linux)No route to host40615 — Azure SQL: Cannot open server 'x' requested by the login. Client with IP address 'y' is not allowed to access the server (Error 40615) (Azure)40615ssh port 22 Connection timed out — ssh: connect to host x port 22: Connection timed out (Linux)ssh port 22 Connect…Idle connections silently dropped by firewall/NAT — Networking: Connection works, then fails after being idle — firewall/NAT idle timeout dropped the TCP session (use keepalive) (Networking)Idle connections si…PING: transmit failed. General failure. — Networking: PING: transmit failed. General failure. / ping: sendmsg: Operation not permitted (Networking)PING: transmit fail…nc/telnet hangs: firewall DROP vs REJECT — Networking: nc -vz hangs then times out — firewall silently DROPs packets (REJECT would answer "Connection refused") (Networking)nc/telnet hangs: fi…Outbound port 25 blocked — SMTP: telnet smtp.example.com 25 — Connection timed out (cloud provider blocks port 25) (Email / SMTP)Outbound port 25 bl…webhook signature — Webhook signature verification failed (Stripe, Razorpay, GitHub…) (API)webhook signatureviolates PodSecurity — Error creating: pods is forbidden: violates PodSecurity "restricted:latest": allowPrivilegeEscalation != false ... (Kubernetes)violates PodSecurityREMOTE HOST IDENTIFICATION HAS CHANGED — WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! (ssh host key changed) (Linux)REMOTE HOST IDENTIF…NO_PUBKEY — The following signatures couldn't be verified because the public key is not available: NO_PUBKEY (Linux)NO_PUBKEY1009 — Cloudflare Error 1009: Access denied — The owner of this website has banned the country or region your IP address is in (Cloudflare)10091010 — Cloudflare Error 1010: The owner of this website has banned your access based on your browser's signature (Cloudflare)1010403 — HTTP 403 Forbidden (HTTP)403429 — HTTP 429 Too Many Requests (HTTP)429520 — Cloudflare Error 520: Web Server Returned an Unknown Error (Cloudflare)5201011 — Cloudflare Error 1011: Access denied (Hotlinking denied) (Cloudflare)10111015 — Cloudflare Error 1015: You are being rate limited (Cloudflare)1015SecurityException: Permission Denial — java.lang.SecurityException: Permission Denial ... requires android.permission.X (Android)SecurityException: …EADDRINUSE — Error: listen EADDRINUSE: address already in use :::3000 (Node.js)EADDRINUSEport is already allocated — Docker: Bind for 0.0.0.0:80 failed: port is already allocated (Docker)port is already all…Port 8080 in use — Web server failed to start. Port 8080 was already in use. (Java)Port 8080 in useECONNREFUSED — Error: connect ECONNREFUSED 127.0.0.1:5432 (Node.js)ECONNREFUSEDECONNRESET — Error: socket hang up / read ECONNRESET (API)ECONNRESETssh port 22 Connection refused — ssh: connect to host x port 22: Connection refused (Linux)ssh port 22 Connect…18456 — SQL Server: Login failed for user 'x'. (Error 18456) (SQL)18456Login failed for user '<token-identified principal>' — Azure SQL: Login failed for user '<token-identified principal>' (Microsoft Entra / managed identity) (Azure)Login failed for us…port 22 timed out — ssh: connect to host github.com port 22: Connection timed out (Git)port 22 timed outkex_exchange_identification — kex_exchange_identification: Connection closed by remote host (Git)kex_exchange_identi…Network is unreachable — connect: Network is unreachable (ENETUNREACH) (Linux)Network is unreacha…client_loop: send disconnect: Broken pipe — client_loop: send disconnect: Broken pipe (SSH session drops when idle) (Linux)client_loop: send d…ECONNRESET / Connection reset by peer on idle Redis connection — Redis: Error: read ECONNRESET / redis.exceptions.ConnectionError: Connection reset by peer after idle time (Redis)ECONNRESET / Connec…Public IP/domain unreachable from inside the LAN (NAT hairpin) — Networking: Server reachable from the internet but not from inside the LAN via its public IP — NAT loopback / hairpin NAT not working (Networking)Public IP/domain un…WSL 2 installation is incomplete — Docker Desktop: WSL 2 installation is incomplete / WSL update required (Docker)WSL 2 installation …Network cable unplugged / NO-CARRIER — Networking: Network cable unplugged / `ip link` shows NO-CARRIER state DOWN / Ethernet: Network cable unplugged (Networking)Network cable unplu…No Wi-Fi adapter found / Wi-Fi option missing — Networking: No Wi-Fi networks found — the Wi-Fi adapter is missing, disabled or its driver failed (Networking)No Wi-Fi adapter fo…ERR_CONNECTION_TIMED_OUT — ERR_CONNECTION_TIMED_OUT: This site can’t be reached — example.com took too long to respond (Browser)ERR_CONNECTION_TIME…Port forwarding not working (CGNAT / double NAT) — Networking: Port forwarding configured but the port stays closed — carrier-grade NAT (CGNAT) or double NAT (Networking)Port forwarding not…Cannot assign requested address (EADDRNOTAVAIL) — Networking: connect: Cannot assign requested address — ephemeral port range exhausted by TIME_WAIT connections (Networking)Cannot assign reque…421 4.7.0 Try again later (rate limited) — SMTP: 421 4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address. Mail sent from your IP address has been temporarily rate limited (Email / SMTP)421 4.7.0 Try again…450 4.7.1 Greylisted, please try again later — SMTP: 450 4.7.1 <user@example.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/example.com.html (Email / SMTP)450 4.7.1 Greyliste…451 4.3.0 Local error in processing — SMTP: 451 4.3.0 Error: queue file write error / 451 Requested action aborted: local error in processing (Email / SMTP)451 4.3.0 Local err…

Directly related (12)

1005Cloudflare

Cloudflare Error 1005: Access denied — The owner of this website has banned the autonomous system number (ASN) your IP address is in

The site owner blocked your network provider (ASN) — common for VPNs, cloud/data-center IPs and some mobile carriers.

1006Cloudflare

Cloudflare Error 1006 / 1007 / 1008: Access denied — Your IP address has been banned

The site owner (or a Cloudflare security setting) blocked your IP address.

1020Cloudflare

Cloudflare Error 1020: Access Denied

A Cloudflare firewall/WAF custom rule blocked the request — the visitor’s IP, country, user agent or request pattern matched a bl…

1012Cloudflare

Cloudflare Error 1012: Access denied

The site owner blocked access with a rule that matched your request (often due to malicious activity detected from your IP).

iptables: No chain/target/matchDocker

driver failed programming external connectivity on endpoint: iptables: No chain/target/match by that name

Docker’s iptables rules were wiped (firewalld/ufw reload, iptables flush) while Docker was running, so it can’t publish ports.

No route to hostLinux

connect: No route to host (EHOSTUNREACH)

The destination host isn’t reachable — it’s down, on another subnet without routing, or a firewall rejects with “host unreachable…

40615Azure

Azure SQL: Cannot open server 'x' requested by the login. Client with IP address 'y' is not allowed to access the server (Error 40615)

The Azure SQL server firewall doesn’t allow your client’s IP address.

ssh port 22 Connection timed outLinux

ssh: connect to host x port 22: Connection timed out

SSH packets get no reply — a firewall/security group drops them, the server is off, or the IP is wrong.

Idle connections silently dropped by firewall/NATNetworking

Networking: Connection works, then fails after being idle — firewall/NAT idle timeout dropped the TCP session (use keepalive)

A connection that sat idle was forgotten by a firewall or NAT device, so the next packet gets reset or vanishes.

PING: transmit failed. General failure.Networking

Networking: PING: transmit failed. General failure. / ping: sendmsg: Operation not permitted

The operating system could not even send the packet, so the problem is local (adapter, route or firewall), not the remote host.

nc/telnet hangs: firewall DROP vs REJECTNetworking

Networking: nc -vz hangs then times out — firewall silently DROPs packets (REJECT would answer "Connection refused")

A connection attempt gets no answer at all, which points to a firewall dropping the packets rather than a closed port.

Outbound port 25 blockedEmail / SMTP

SMTP: telnet smtp.example.com 25 — Connection timed out (cloud provider blocks port 25)

Connections from your server to other mail servers on port 25 time out because your cloud host or ISP blocks outbound SMTP to fig…

Two steps away (35)

webhook signatureAPI

Webhook signature verification failed (Stripe, Razorpay, GitHub…)

Your endpoint computed a different HMAC signature than the one the provider sent, so the webhook is rejected.

violates PodSecurityKubernetes

Error creating: pods is forbidden: violates PodSecurity "restricted:latest": allowPrivilegeEscalation != false ...

The namespace enforces a Pod Security Standard (baseline/restricted) and the pod spec breaks one of its rules.

REMOTE HOST IDENTIFICATION HAS CHANGEDLinux

WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! (ssh host key changed)

The server’s SSH host key differs from the one saved in ~/.ssh/known_hosts — usually because the server was rebuilt or the IP was…

NO_PUBKEYLinux

The following signatures couldn't be verified because the public key is not available: NO_PUBKEY

apt can’t verify a repository’s signature because the repo’s signing key isn’t installed (or has expired/rotated).

1009Cloudflare

Cloudflare Error 1009: Access denied — The owner of this website has banned the country or region your IP address is in

The site blocks visitors from your country/region.

1010Cloudflare

Cloudflare Error 1010: The owner of this website has banned your access based on your browser's signature

Cloudflare’s bot detection blocked the request because its browser fingerprint looks automated.

403HTTP

HTTP 403 Forbidden

The server understood the request but refuses to authorize it — you (or the server process) are not allowed to access this resour…

429HTTP

HTTP 429 Too Many Requests

You’ve hit a rate limit — too many requests in a given time window. Slow down and retry later.

520Cloudflare

Cloudflare Error 520: Web Server Returned an Unknown Error

Cloudflare connected to your origin, but the origin returned an empty, unknown or invalid response.

1011Cloudflare

Cloudflare Error 1011: Access denied (Hotlinking denied)

An image or file is being loaded from another site, and Cloudflare Hotlink Protection blocked it.

1015Cloudflare

Cloudflare Error 1015: You are being rate limited

The site’s Cloudflare rate-limiting rule blocked you for sending too many requests in a short time.

SecurityException: Permission DenialAndroid

java.lang.SecurityException: Permission Denial ... requires android.permission.X

The app called an API that needs a permission it hasn’t declared or the user hasn’t granted at runtime.

EADDRINUSENode.js

Error: listen EADDRINUSE: address already in use :::3000

Another process is already listening on that port.

port is already allocatedDocker

Docker: Bind for 0.0.0.0:80 failed: port is already allocated

Another container or host process already publishes that host port.

Port 8080 in useJava

Web server failed to start. Port 8080 was already in use.

Spring Boot couldn’t bind its embedded server port because another process uses it.

ECONNREFUSEDNode.js

Error: connect ECONNREFUSED 127.0.0.1:5432

Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.

ECONNRESETAPI

Error: socket hang up / read ECONNRESET

The other side closed the TCP connection abruptly while your client was still using it.

ssh port 22 Connection refusedLinux

ssh: connect to host x port 22: Connection refused

The server answered, but nothing is listening on the SSH port — sshd isn’t running, it uses another port, or a firewall actively…

18456SQL

SQL Server: Login failed for user 'x'. (Error 18456)

SQL Server rejected the login — wrong password, wrong authentication mode, or a disabled/missing login.

Login failed for user '<token-identified principal>'Azure

Azure SQL: Login failed for user '<token-identified principal>' (Microsoft Entra / managed identity)

Entra ID authentication succeeded, but there’s no database user for that identity (or it lacks permission to the database).

port 22 timed outGit

ssh: connect to host github.com port 22: Connection timed out

Outbound SSH on port 22 is blocked (firewall, corporate or public Wi-Fi).

kex_exchange_identificationGit

kex_exchange_identification: Connection closed by remote host

The SSH connection was closed before the handshake — server overload, rate limiting, or a proxy/firewall interfering.

Network is unreachableLinux

connect: Network is unreachable (ENETUNREACH)

The host has no route to the destination network — no default gateway, interface down, or trying IPv6 without IPv6 connectivity.

client_loop: send disconnect: Broken pipeLinux

client_loop: send disconnect: Broken pipe (SSH session drops when idle)

The SSH connection was cut — usually an idle timeout on a NAT router, firewall or the server, sometimes a network change.

ECONNRESET / Connection reset by peer on idle Redis connectionRedis

Redis: Error: read ECONNRESET / redis.exceptions.ConnectionError: Connection reset by peer after idle time

A middlebox or Redis closed an idle connection, and the pooled client reused it.

Public IP/domain unreachable from inside the LAN (NAT hairpin)Networking

Networking: Server reachable from the internet but not from inside the LAN via its public IP — NAT loopback / hairpin NAT not working

Devices on your own network can't use the router's public address to reach a server that is also on that network.

WSL 2 installation is incompleteDocker

Docker Desktop: WSL 2 installation is incomplete / WSL update required

Docker Desktop on Windows needs WSL 2 and its Linux kernel; they’re missing, outdated or disabled.

Network cable unplugged / NO-CARRIERNetworking

Networking: Network cable unplugged / `ip link` shows NO-CARRIER state DOWN / Ethernet: Network cable unplugged

The network card sees no electrical link, so nothing above it (IP, DNS, browser) can work.

No Wi-Fi adapter found / Wi-Fi option missingNetworking

Networking: No Wi-Fi networks found — the Wi-Fi adapter is missing, disabled or its driver failed

The operating system doesn't see a working wireless adapter, so no networks can be listed.

ERR_CONNECTION_TIMED_OUTBrowser

ERR_CONNECTION_TIMED_OUT: This site can’t be reached — example.com took too long to respond

The browser waited for the server but got no response — the server is down/unreachable, a firewall drops traffic, or DNS points t…

Port forwarding not working (CGNAT / double NAT)Networking

Networking: Port forwarding configured but the port stays closed — carrier-grade NAT (CGNAT) or double NAT

Your router forwards the port correctly, but another NAT in front of it (your ISP or a second router) blocks inbound connections.

Cannot assign requested address (EADDRNOTAVAIL)Networking

Networking: connect: Cannot assign requested address — ephemeral port range exhausted by TIME_WAIT connections

The machine ran out of local ports for new outgoing connections to the same destination.

421 4.7.0 Try again later (rate limited)Email / SMTP

SMTP: 421 4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address. Mail sent from your IP address has been temporarily rate limited

The receiving server (often Gmail or Outlook) is temporarily throttling your mail because the volume or reputation of your sendin…

450 4.7.1 Greylisted, please try again laterEmail / SMTP

SMTP: 450 4.7.1 <user@example.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/example.com.html

The recipient server deliberately rejected the first delivery attempt from an unknown sender (greylisting) and expects a legitima…

451 4.3.0 Local error in processingEmail / SMTP

SMTP: 451 4.3.0 Error: queue file write error / 451 Requested action aborted: local error in processing

The server hit an internal problem (disk, database, content filter, DNS) while handling your message and asked you to retry later.