erx.sh

#!/usr/bin/env bash
set -u
# script gen debug info for edge router X
# any interface it ought to be helpful
# sudo ./erx.sh interface
# sudo ./erx.sh enp2s0
IFACE="${1:-enp2s0}"
LOG="erx_diag_$(date +%Y%m%d_%H%M%S).log"

say() { echo -e "\n=== $* ===" | tee -a "$LOG"; }
run() { echo "\$ $*" | tee -a "$LOG"; "$@" 2>&1 | tee -a "$LOG"; }

need_root() {
  if [[ "$EUID" -ne 0 ]]; then
    echo "Run as root: sudo $0 [$IFACE]"
    exit 1
  fi
}

check_cmd() {
  command -v "$1" >/dev/null 2>&1
}

need_root

say "EdgeRouter X client-side diagnostic"
echo "Interface: $IFACE" | tee -a "$LOG"
echo "Log: $LOG" | tee -a "$LOG"

say "1. Link state"
run ip link show "$IFACE"

if ! ip link show "$IFACE" | grep -q "LOWER_UP"; then
  echo "RESULT: No physical link. Check cable, port, router power, or wrong interface." | tee -a "$LOG"
  exit 1
fi

echo "RESULT: Physical Ethernet link is up." | tee -a "$LOG"

say "2. Current IP addresses"
run ip addr show "$IFACE"

if ip -4 addr show "$IFACE" | grep -q "inet "; then
  echo "RESULT: You already have an IPv4 address." | tee -a "$LOG"
else
  echo "RESULT: No IPv4 address currently assigned." | tee -a "$LOG"
fi

say "3. Routes"
run ip route

say "4. NetworkManager status, if available"
if check_cmd nmcli; then
  run nmcli dev status
  run nmcli dev show "$IFACE"
else
  echo "nmcli not installed/skipped." | tee -a "$LOG"
fi

say "5. DHCP attempt"
if check_cmd dhclient; then
  run dhclient -r "$IFACE"
  timeout 20 dhclient -v "$IFACE" 2>&1 | tee -a "$LOG"
  DHCP_RC=${PIPESTATUS[0]}
elif check_cmd udhcpc; then
  timeout 20 udhcpc -i "$IFACE" -n -q 2>&1 | tee -a "$LOG"
  DHCP_RC=${PIPESTATUS[0]}
else
  echo "No dhclient or udhcpc found. Cannot actively test DHCP." | tee -a "$LOG"
  DHCP_RC=99
fi

say "6. IP after DHCP"
run ip addr show "$IFACE"
run ip route

if ip -4 addr show "$IFACE" | grep -q "inet "; then
  IP=$(ip -4 addr show "$IFACE" | awk '/inet / {print $2; exit}')
  GW=$(ip route | awk '/default/ {print $3; exit}')
  echo "RESULT: DHCP or addressing succeeded. IP: $IP Gateway: ${GW:-none}" | tee -a "$LOG"

  if [[ -n "${GW:-}" ]]; then
    say "7. Gateway ping"
    run ping -c 3 -W 2 "$GW"
  fi

  exit 0
fi

say "7. Passive DHCP packet sniff"
if check_cmd tcpdump; then
  echo "Listening briefly for DHCP traffic. Unplug/replug the Ethernet cable now if you want." | tee -a "$LOG"
  timeout 15 tcpdump -ni "$IFACE" -vvv 'port 67 or port 68' 2>&1 | tee -a "$LOG"
else
  echo "tcpdump not installed/skipped." | tee -a "$LOG"
fi

say "Diagnosis"

echo "Physical link: OK" | tee -a "$LOG"
echo "IPv4 address: MISSING" | tee -a "$LOG"

cat <<EOF | tee -a "$LOG"

Most likely causes:

1. The EdgeRouter port you are plugged into is not configured as LAN.
   On many EdgeRouter X configs, eth1-eth4 need to be members of switch0.

2. DHCP server is not configured or not running on that LAN interface.

3. The router may be factory-reset or configured with a static LAN address only.
   Try setting your computer manually to:
     IP:      192.168.1.10
     Netmask: 255.255.255.0
   Then try:
     ping 192.168.1.1
     ssh [email protected]
     open http://192.168.1.1/

4. If this is not a default config, the LAN may be on another subnet/VLAN.

Useful router-side commands, if you can console/SSH into it:

  show interfaces
  show interfaces switch
  show service dhcp-server
  show configuration commands | match "eth1|switch0|dhcp-server"

Saved full diagnostic log to:
  $LOG
EOF
# post scan debug
#sudo nmcli radio wifi off
#sudo ip addr flush dev enp2s0
#sudo ip addr add 192.168.1.10/24 dev enp2s0
#sudo ip link set enp2s0 up
#ping -c 3 192.168.1.1