Add router Wi-Fi fix diagnostic script

2026-09-23 05:08:59 +02:00
parent 43bfab63aa
commit dde29ff421
1 changed files with 95 additions and 0 deletions
@@ -0,0 +1,95 @@
+#!/usr/bin/env bash
+#===============================================================================
+# archer_router_wifi_fix.sh — diagnose a "stuck" home router
+#
+# SUMMARY (context from the TP-Link/Archer troubleshooting session):
+#   Symptom: Wi-Fi associates with full signal, DHCP lease obtained, but the
+#   router's own IPv4 (ping, admin page, DNS, IPv4 internet) is unreachable over
+#   WLAN. IPv6, DHCP and client-to-client bridging may still work — this is the
+#   classic "half-wedged" router: the management plane is hung, so a web/browser
+#   "Reboot" button often never executes.
+#   Fix: HARD power-cycle (unplug 30–60 s, replug, wait ~2 min). Verify Wi-Fi
+#   in isolation (bind each test to an interface) so an ethernet cable / second
+#   NIC can't mask the result. If it still hangs with stock firmware, replace
+#   the unit.
+#
+# USE:  bash archer_router_wifi_fix.sh            # full diagnostic
+#       bash archer_router_wifi_fix.sh wifi       # verify Wi-Fi path only (post-reboot)
+#       exit codes: 0 = all healthy, 1 = at least one check failed
+#===============================================================================
+set -u
+FAIL=0
+MODE="${1:-all}"                       # all | wifi
+
+log()  { printf '\033[1;34m[%s]\033[0m %s\n' "$(date +%H:%M:%S)" "$*"; }
+ok()   { printf '    \033[1;32mPASS\033[0m %s\n' "$*"; }
+bad()  { printf '    \033[1;31mFAIL\033[0m %s\n' "$*"; FAIL=1; }
+
+#--- targets ---------------------------------------------------------------
+GW=$(ip -4 route show default | awk '/^default/{print $3; exit}')
+IFACES=$(ip -4 -o addr show scope global | awk '{print $2}' | sort -u)
+
+# if only wifi, filter to wireless NICs
+if [ "$MODE" = "wifi" ]; then
+  IFACES=$(iw dev 2>/dev/null | awk '/Interface/{print $2}')
+fi
+
+log "Gateway (IPv4): ${GW:-NONE (no default route)}"
+log "Interfaces to test: $IFACES"
+
+#--- per-interface checks --------------------------------------------------
+for I in $IFACES; do
+  [ -n "$I" ] || continue
+  IP=$(ip -4 -o addr show dev "$I" scope global | awk '{print $4}')
+  log "== $I  ($IP) =="
+
+  [ -n "$IP" ] && ok "has IPv4 $IP" || { bad "no IPv4 on $I"; continue; }
+
+  if [ -n "$GW" ]; then
+    if ping -I "$I" -c 3 -W 2 "$GW" >/dev/null 2>&1; then
+      ok "ping $GW on $I"
+    else
+      bad "ping $GW on $I"
+      if [ "$MODE" != "wifi" ]; then
+        printf '      > router not answering IPv4 on %s — try HARD power-cycle\n' "$I"
+      fi
+    fi
+  fi
+
+  if curl -sI -m 6 --interface "$I" "http://$GW" -o /dev/null >/dev/null 2>&1; then
+    ok "admin page http://$GW reachable"
+  else
+    bad "admin page http://$GW not reachable"
+  fi
+
+  if curl -sI -m 8 --interface "$I" https://example.com -o /dev/null >/dev/null 2>&1; then
+    ok "IPv4 internet via $I (example.com)"
+  else
+    bad "IPv4 internet via $I"
+  fi
+
+  # IPv6 path (optional signal)
+  if ping -6 -c 2 -W 2 "fe80::1%$I" >/dev/null 2>&1; then
+    ok "IPv6 link-local reachable (router alive on v6)"
+  else
+    log "IPv6 check skipped/absent on $I"
+  fi
+done
+
+#--- DNS ------------------------------------------------------------------
+log "DNS"
+if getent hosts example.com >/dev/null 2>&1; then
+  ok "system DNS resolves"
+else
+  bad "system DNS does not resolve"
+fi
+
+printf '\n'
+if [ "$FAIL" -eq 0 ]; then
+  log "RESULT: all checks OK"
+else
+  log "RESULT: failures found -> if the 'ping <gateway>' failed above, do a"
+  log "        HARD power-cycle of the router (unplug 30–60s), wait 2 min,"
+  log "        then re-run:  bash archer_router_wifi_fix.sh wifi"
+fi
+exit $FAIL