Error map
Cannot assign requested address (EADDRNOTAVAIL) Networking: connect: Cannot assign requested address — ephemeral port range exhausted by TIME_WAIT connections
Networking · layer 2, Network
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.
Directly related (12)
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.
Networking: wlan0: WPA: 4-way handshake failed - pre-shared key may be incorrect / WRONG_KEY
The Wi-Fi association started but key negotiation failed, almost always a wrong password.
Networking: %CDP-4-NATIVE_VLAN_MISMATCH / device on the wrong VLAN can't reach the gateway
A port or trunk carries a different VLAN than expected, so hosts silently land on the wrong network.
Networking: %PM-4-ERR_DISABLE: psecure-violation error detected on Gi0/5, putting Gi0/5 in err-disable state
The switch shut the port down because a security or protection feature detected a violation.
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.
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.
Networking: netstat -s: segments retransmitted / Wireshark: TCP Retransmission, TCP Dup ACK — packet loss on the path
Packets are being lost, so TCP resends them and throughput collapses.
Networking: NAT gateway ErrorPortAllocation / SNAT port exhaustion — intermittent outbound connection timeouts
Many instances share few public IPs, and the NAT gateway runs out of source ports for outbound connections.
Networking: TCP: request_sock_TCP: Possible SYN flooding on port 80. Sending cookies. Check SNMP counters.
The server's pending-connection queue filled, so the kernel switched to SYN cookies to survive.
Networking: netstat -su: packet receive errors, receive buffer errors — UDP datagrams dropped by a full socket buffer
UDP packets arrive faster than the application reads them, so the kernel throws the extras away.
Networking: kernel: nf_conntrack: table full, dropping packet — new connections fail on a Linux firewall/NAT host
The connection-tracking table is full, so the kernel drops packets for any new connection.
Networking: kernel: nfs: server nas01 not responding, still trying / nfs: server nas01 OK
An NFS client can't get replies from the server, so processes using the mount hang in uninterruptible sleep.
Two steps away (30)
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.
Chrome: No internet — ERR_INTERNET_DISCONNECTED (You are not connected to the internet)
Chrome sees no working network connection on the device, so it cannot load any page.
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.
Browser: This network requires you to sign in — captive portal (hotel, airport, café Wi-Fi) blocking HTTPS sites
The Wi-Fi needs a login or acceptance page first; until you complete it, secure sites fail with certificate or connection errors.
Networking: Wi-Fi keeps disconnecting / signal -80 dBm / wlan0: deauthenticating by local choice (reason=3)
The wireless link is too weak or too noisy to hold, so the client drops and rejoins repeatedly.
Networking: `arp -n` shows (incomplete) / Destination Host Unreachable — no ARP reply from the next hop
The machine asked "who has this IP?" and nobody on the local network answered.
Networking: Duplex mismatch — late collisions, runts and CRC errors on the switch port
One side runs full duplex and the other half duplex, so the link works but is slow and drops packets.
Networking: %SW_MATM-4-MACFLAP_NOTIF: Host is flapping between ports / broadcast storm
A layer-2 loop is making frames circle the network, saturating links and making the whole VLAN crawl.
Networking: %OSPF-5-ADJCHG: Nbr 10.0.0.2 from EXSTART to DOWN — OSPF neighbor stuck in EXSTART/EXCHANGE (MTU mismatch)
Two OSPF routers see each other but never finish exchanging databases, cycling between EXSTART and DOWN.
Networking: Interface down — SFP transceiver Loss of Signal / no receive light
A fibre or SFP link is down because the transceiver receives no light.
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.
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.
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.
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…
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…
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.
Networking: SSH/HTTPS connects but hangs on large data — path MTU discovery black hole
Small packets pass but full-size ones vanish, so logins work and then transfers or page loads stall.
Networking: Wireshark: TCP ZeroWindow, TCP Window Full — the receiver can't keep up and tells the sender to stop
The receiving application isn't reading data fast enough, so its TCP buffer filled and the sender must pause.
Networking: Thousands of sockets in CLOSE_WAIT — the application is not closing its side of the connection
The other end closed the connection, but your program never called close(), so the socket stays open.
Docker: Bind for 0.0.0.0:80 failed: port is already allocated
Another container or host process already publishes that host port.
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.
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nginx (or another server) can’t listen on the port because another process already holds it — often Apache, another Nginx, or a s…
Cloudflare-branded 502 Bad Gateway / 504 Gateway Timeout ("cloudflare" footer)
A plain-looking 502/504 page with “cloudflare” at the bottom comes from Cloudflare’s network itself (or an origin response it cou…
Networking: netstat -s: 1523 times the listen queue of a socket overflowed — accept queue full, connections dropped
The application accepts connections slower than they arrive, so the kernel's accept queue overflows.
Networking: ICMP Destination unreachable (Port unreachable) — UDP packet sent to a port where nothing is listening
A host answered a UDP packet with an ICMP message saying no program is listening on that port.
Networking: Handshake for peer did not complete after 5 seconds, retrying (try 2) — WireGuard tunnel never establishes
The WireGuard peers can't complete the cryptographic handshake, so no traffic flows.
DNS not working inside a Kubernetes pod (could not resolve host / nslookup: can't resolve)
Pods can’t resolve service names or external hosts — CoreDNS is down, blocked by NetworkPolicy, or the upstream resolver fails.
Networking: dhclient: DHCPDISCOVER on eth0 ... No DHCPOFFERS received. No working leases in persistent database - sleeping.
The client broadcast a DHCP request and no server answered.
Networking: Every connection pauses about 5 seconds — resolv.conf nameserver timeout, then fallback to the next DNS server
The first DNS server in the list isn't answering, so each lookup waits out a timeout before trying the next one.
Networking: Windows error 64: The specified network name is no longer available — SMB session dropped
A connection to a Windows file share was cut while in use.
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