Check Interface Status

• Using Bash script

• Collect list of indexes from ifAlias

#!/bin/bash

# Parse command-line arguments
while getopts "H:u:a:p:A:X:t:" opt; do
  case $opt in
    H) HOST="$OPTARG" ;;
    u) USER="$OPTARG" ;;
    a) AUTH_PASS="$OPTARG" ;;
    p) PRIV_PASS="$OPTARG" ;;
    A) AUTH_PROTO="$OPTARG" ;;
    X) PRIV_PROTO="$OPTARG" ;;
    t) TAG="$OPTARG" ;;
    *)
      echo "Usage: $0 -H host -u user -a auth_pass -p priv_pass -A auth_proto -X priv_proto"
      exit 3
      ;;
  esac
done

# Validate inputs
if [[ -z "$HOST"  -z "$USER"  -z "$AUTH_PASS"  -z "$PRIV_PASS"  -z "$AUTH_PROTO" || -z "$PRIV_PROTO" ]]; then
  echo "UNKNOWN - Missing required arguments"
  exit 3
fi

# Set default Tag
[[ -z "$TAG" ]] && TAG="[M"

#OIDs
IFNAME_OID="1.3.6.1.2.1.31.1.1.1.1"
IFALIAS_OID="1.3.6.1.2.1.31.1.1.1.18"
IFADMINSTATUS_OID="1.3.6.1.2.1.2.2.1.7"
IFOPERSTATUS_OID="1.3.6.1.2.1.2.2.1.8"

# Get interface aliases (descriptions)
ALIASES=$(snmpwalk -v3 -u "$USER" -a "$AUTH_PROTO" -A "$AUTH_PASS" -x "$PRIV_PROTO" -X "$PRIV_PASS" -l authPriv "$HOST" "$IFALIAS_OID" -On 2>/dev/null)
echo $ALIASES
Track interfaces with $TAG and not up/up
declare -a BAD_INTERFACES=()
declare -a GOOD_INTERFACES=()

# Loop through alias lines
while read -r line; do
 # Extract index and alias
 #index=$(echo "$line" | awk -F '.' '{print $NF}' | awk '{print $1}')
 # Step 1: Get the part before the equal sign
 oid_part=$(echo "$line" | cut -d '=' -f1 | tr -d ' ')

 # Step 2: Extract the index (last digit after the final dot)
 index=$(echo "$oid_part" | awk -F '.' '{print $NF}')

 alias=$(echo "$line" | cut -d ':' -f2- | xargs)

 # Check for [M in alias
 if [[ "$alias" == "$TAG" ]]; then
   # Get interface name
   IF_NAME=$(snmpget -v3 -u "$USER" -a "$AUTH_PROTO" -A "$AUTH_PASS" -x "$PRIV_PROTO" -X "$PRIV_PASS" -l authPriv "$HOST" "$IFNAME_OID.$index" -Ovq 2>/dev/null)
   ADMIN_STATUS=$(snmpget -v3 -u "$USER" -a "$AUTH_PROTO" -A "$AUTH_PASS" -x "$PRIV_PROTO" -X "$PRIV_PASS" -l authPriv "$HOST" "$IFADMINSTATUS_OID.$index" -Ovq 2>/dev/null)
   OPER_STATUS=$(snmpget -v3 -u "$USER" -a "$AUTH_PROTO" -A "$AUTH_PASS" -x "$PRIV_PROTO" -X "$PRIV_PASS" -l authPriv "$HOST" "$IFOPERSTATUS_OID.$index" -Ovq 2>/dev/null)
   echo "$IF_NAME" "$ADMIN_STATUS" "$OPER_STATUS"
   if [[ "$ADMIN_STATUS" != "up" || "$OPER_STATUS" != "up" ]]; then
     BAD_INTERFACES+=("$IF_NAME - $alias - (Admin: $ADMIN_STATUS, Oper: $OPER_STATUS)")
   else
     GOOD_INTERFACES+=("$IF_NAME - $alias - (Admin: $ADMIN_STATUS, Oper: $OPER_STATUS)")
   fi

 fi
done <<< "$ALIASES"

# Output result
if [[ ${#BAD_INTERFACES[@]} -gt 0 ]]; then
  echo "CRITICAL - Monitored interfaces are not in up/up state:"
  for iface in "${BAD_INTERFACES[@]}"; do
    echo "  $iface"
  done
  exit 2
elif [[ ${#GOOD_INTERFACES[@]} -gt 0 ]]; then
  echo "OK - All monitored interfaces are up/up"
  for iface in "${GOOD_INTERFACES[@]}"; do
    echo "  $iface"
  done
  exit 0
else
  echo "OK - No interface with $TAG found"
fi

Python

• Using Python

• Collect list of indexes from ifAlias

#!/usr/bin/env python3

import os
import sys
import time
import argparse
import signal
import subprocess

# Constants
STATUS_OK       = 0
STATUS_WARNING  = 1
STATUS_CRITICAL = 2
STATUS_UNKNOWN  = 3
TIMEOUT         = 55
DEBUG           = False

# Timeout handler
def handle_timeout(signum, frame):
    print(f"UNKNOWN - Script timed out after {TIMEOUT} seconds")
    sys.exit(STATUS_UNKNOWN)

# Wrapper around snmpwalk
def run_snmpwalk(oid, host, user, auth_pass, priv_pass, auth_proto, priv_proto):
    cmd = [
        "snmpwalk", "-v3", "-u", user,
        "-a", auth_proto, "-A", auth_pass,
        "-x", priv_proto, "-X", priv_pass,
        "-l", "authPriv", host, oid,
        "-Oqv"
    ]
    try:
        out = subprocess.check_output(cmd,
                                      stderr=subprocess.DEVNULL,
                                      text=True)
        lines = [l.strip() for l in out.splitlines() if l.strip()]
        if DEBUG:
            print(f"DEBUG: snmpwalk {oid} → {lines}")
        return lines
    except subprocess.CalledProcessError:
        return []

def main():
    global DEBUG
    global TIMEOUT

    # === Argument parsing ===
    p = argparse.ArgumentParser(description="Check SNMPv3 interfaces for up/up state")
    p.add_argument("-H","--host",       required=True, help="SNMP agent host")
    p.add_argument("-u","--user",       required=True, help="SNMPv3 username")
    p.add_argument("-a","--auth_pass",  required=True, help="SNMPv3 auth password")
    p.add_argument("-A","--auth_proto", required=True, choices=["MD5","SHA"],
                   help="SNMPv3 auth protocol")
    p.add_argument("-p","--priv_pass",  required=True, help="SNMPv3 priv password")
    p.add_argument("-X","--priv_proto", required=True, choices=["DES","AES"],
                   help="SNMPv3 priv protocol")
    p.add_argument("-t","--tag",        default="[M", help="Alias tag to monitor")
    p.add_argument("--debug",           action="store_true", help="Enable debug output")
    p.add_argument("--timeout", type=int, default=TIMEOUT,
                   help="Script timeout in seconds")
    args = p.parse_args()

    # === Setup timeout ===
    signal.signal(signal.SIGALRM, handle_timeout)
    if args.timeout:
      signal.alarm(TIMEOUT=args.timeout)
    else:
      signal.alarm(TIMEOUT)

    if args.debug:
        DEBUG = True

    wanted_keys = ['host','user','auth_pass','priv_pass','auth_proto','priv_proto']
    subset = {k:v for k,v in vars(args).items() if k in wanted_keys}
    sub_args = argparse.Namespace(**subset)

    # OID bases
    IFALIAS_OID       = "1.3.6.1.2.1.31.1.1.1.18"
    IFNAME_OID        = "1.3.6.1.2.1.31.1.1.1.1"
    IFADMINSTATUS_OID = "1.3.6.1.2.1.2.2.1.7"
    IFOPERSTATUS_OID  = "1.3.6.1.2.1.2.2.1.8"

    # === Fetch SNMP tables ===
    aliases = run_snmpwalk(IFALIAS_OID, **vars(sub_args))
    if not aliases:
        print("UNKNOWN - No SNMP data returned or error")
        sys.exit(STATUS_UNKNOWN)

    bad_interfaces = []
    good_interfaces = []

    # === Process each alias entry ===
    # alias lines look like: "<aliasValue>"
    # but in `-Oqv` form it's just the value
    # we need the index; so we re-walk with "-On" to extract OID+value
    raw = subprocess.check_output([
        "snmpwalk", "-v3", "-u", args.user,
        "-a", args.auth_proto, "-A", args.auth_pass,
        "-x", args.priv_proto, "-X", args.priv_pass,
        "-l", "authPriv", args.host, IFALIAS_OID, "-On"
    ], stderr=subprocess.DEVNULL, text=True).splitlines()

    for line in raw:
        # Format: .1.3.6.1.2.1.31.1.1.1.18.<idx> = "alias"
        parts = line.split("=",1)
        if len(parts) != 2:
            continue
        oid_part, alias_val = parts
        idx = oid_part.strip().rsplit(".",1)[-1]
        alias_val = alias_val.strip().strip('"')

        # Filter by tag
        if args.tag not in alias_val:
            continue

        # Now fetch ifName, adminStatus, operStatus
        def get_one(base_oid):
            out = run_snmpwalk(f"{base_oid}.{idx}", **vars(sub_args))
            return out[0] if out else ""

        ifname      = get_one(IFNAME_OID)
        admin_state = get_one(IFADMINSTATUS_OID)
        oper_state  = get_one(IFOPERSTATUS_OID)

        entry = f"{ifname} - {alias_val} - (Admin: {admin_state}, Oper: {oper_state})"
        # SNMP uses 1=up, 2=down, etc.
        if admin_state != "up" or oper_state != "up":
            bad_interfaces.append(entry)
        else:
            good_interfaces.append(entry)

    # === Output and exit ===
    if bad_interfaces:
        print("WARNING - Monitored interfaces not in up/up state:")
        for e in bad_interfaces:
            print(f"  {e}")
        sys.exit(STATUS_WARNING)

    if good_interfaces:
        print("OK - All monitored interfaces are up/up:")
        for e in good_interfaces:
            print(f"  {e}")
        sys.exit(STATUS_OK)

    # No interfaces matched the tag
    print(f"OK - No interface with tag '{args.tag}' found")
    sys.exit(STATUS_OK)


if __name__ == "__main__":
    main()

Collect indexes from IfName

#!/usr/bin/env python3

import os
import sys
import time
import argparse
import signal
import subprocess

# Constants
STATUS_OK       = 0
STATUS_WARNING  = 1
STATUS_CRITICAL = 2
STATUS_UNKNOWN  = 3
TIMEOUT         = 55
DEBUG           = False

# Timeout handler
def handle_timeout(signum, frame):
    print(f"UNKNOWN - Script timed out after {TIMEOUT} seconds")
    sys.exit(STATUS_UNKNOWN)

# Wrapper around snmpwalk
def run_snmpwalk(oid, host, user, auth_pass, priv_pass, auth_proto, priv_proto):
    cmd = [
        "snmpwalk", "-v3", "-u", user,
        "-a", auth_proto, "-A", auth_pass,
        "-x", priv_proto, "-X", priv_pass,
        "-l", "authPriv", host, oid,
        "-Oqv"
    ]
    try:
        out = subprocess.check_output(cmd,
                                      stderr=subprocess.DEVNULL,
                                      text=True)
        lines = [l.strip() for l in out.splitlines() if l.strip()]
        if DEBUG:
            print(f"DEBUG: snmpwalk {oid} → {lines}")
        return lines
    except subprocess.CalledProcessError:
        return []

def main():
    global DEBUG
    global TIMEOUT

    # === Argument parsing ===
    p = argparse.ArgumentParser(description="Check SNMPv3 interfaces for up/up state")
    p.add_argument("-H","--host",       required=True, help="SNMP agent host")
    p.add_argument("-u","--user",       required=True, help="SNMPv3 username")
    p.add_argument("-a","--auth_pass",  required=True, help="SNMPv3 auth password")
    p.add_argument("-A","--auth_proto", required=True, choices=["MD5","SHA"],
                   help="SNMPv3 auth protocol")
    p.add_argument("-p","--priv_pass",  required=True, help="SNMPv3 priv password")
    p.add_argument("-X","--priv_proto", required=True, choices=["DES","AES"],
                   help="SNMPv3 priv protocol")
    p.add_argument("-t","--tag",        default="[M", help="Alias tag to monitor")
    p.add_argument("--debug",           action="store_true", help="Enable debug output")
    p.add_argument("--timeout", type=int, default=TIMEOUT,
                   help="Script timeout in seconds")
    p.add_argument("--exclude", nargs='*', default=["EFXS", "Voice", "ds0","isdn","proppoint","other","lapd","software", "em", "se", "receive", "E1","Nu"],
               help="List of keywords to exclude based on ifName, default list is  EFSX, voice, ds0, isdn, proppoint, other")
    args = p.parse_args()

    # === Setup timeout ===
    signal.signal(signal.SIGALRM, handle_timeout)
    if args.timeout:
      TIMEOUT=args.timeout
      signal.alarm(TIMEOUT)
    else:
      signal.alarm(TIMEOUT)

    if args.debug:
        DEBUG = True

    wanted_keys = ['host','user','auth_pass','priv_pass','auth_proto','priv_proto']
    subset = {k:v for k,v in vars(args).items() if k in wanted_keys}
    sub_args = argparse.Namespace(**subset)

    # OID bases
    IFALIAS_OID       = "1.3.6.1.2.1.31.1.1.1.18"
    IFNAME_OID        = "1.3.6.1.2.1.31.1.1.1.1"
    IFADMINSTATUS_OID = "1.3.6.1.2.1.2.2.1.7"
    IFOPERSTATUS_OID  = "1.3.6.1.2.1.2.2.1.8"

    # === Fetch SNMP tables ===
    if DEBUG:
        start = time.monotonic()
    # === Process each alias entry ===
    # alias lines look like: "<aliasValue>"
    # but in `-Oqv` form it's just the value
    # we need the index; so we re-walk with "-On" to extract OID+value
    try:
        raw = subprocess.check_output([
            "snmpwalk", "-v3", "-u", args.user,
            "-a", args.auth_proto, "-A", args.auth_pass,
            "-x", args.priv_proto, "-X", args.priv_pass,
            "-l", "authPriv", args.host, IFNAME_OID, "-On"
        ], stderr=subprocess.DEVNULL, text=True).splitlines()
        except subprocess.CalledProcessError:
            raw = []
        except Exception as e:
            print(f"UNKNOWN - SNMP command failed: {e}")
            raw = []
    if DEBUG:
        end = time.monotonic()
        elapsed = end - start
        print(f"SNMPwalk completed in {elapsed:.3f} seconds")

    if not raw:
        print("UNKNOWN - No SNMP interface name data returned")
        sys.exit(STATUS_UNKNOWN)

    bad_interfaces = []
    good_interfaces = []

    for line in raw:
        # Format: .1.3.6.1.2.1.31.1.1.1.1.<idx> = "ifName"
        parts = line.split("=",1)
        if len(parts) != 2:
            continue
        oid_part, ifname_val = parts
        idx = oid_part.strip().rsplit(".",1)[-1]
        ifname_val = ifname_val.strip().strip('"')

        # Apply exclude filters
        if any(excl.lower() in ifname_val.lower() for excl in args.exclude):
            continue

        # Now fetch ifName, adminStatus, operStatus
        def get_one(base_oid):
            out = run_snmpwalk(f"{base_oid}.{idx}", **vars(sub_args))
            return out[0] if out else ""

        alias_val      = get_one(IFALIAS_OID)
        admin_state = get_one(IFADMINSTATUS_OID)
        oper_state  = get_one(IFOPERSTATUS_OID)

        # Optional: Filter by tag in alias if tag is set
        if args.tag and args.tag not in alias_val:
            continue

        entry = f"{ifname_val} - {alias_val} - (Admin: {admin_state}, Oper: {oper_state})"
        # SNMP uses 1=up, 2=down, etc.
        if admin_state != "up" or oper_state != "up":
            bad_interfaces.append(entry)
        else:
            good_interfaces.append(entry)

    # === Output and exit ===
    if bad_interfaces:
        print("WARNING - Monitored interfaces not in up/up state:")
        for e in bad_interfaces:
            print(f"  {e}")
        sys.exit(STATUS_WARNING)

    if good_interfaces:
        print("OK - All monitored interfaces are up/up:")
        for e in good_interfaces:
            print(f"  {e}")
        sys.exit(STATUS_OK)

    # No interfaces matched the tag
    print(f"OK - No interface with tag '{args.tag}' found")
    sys.exit(STATUS_OK)


if __name__ == "__main__":
    main()

Python with bulkwalk to reduce CPU cycles

#!/usr/bin/env python3
"""
SNMPv3 “up/up” checker using separate snmpbulkwalk calls
per column to fetch ifName, ifAlias, ifAdminStatus, ifOperStatus.
"""

import sys
import signal
import argparse
import subprocess

# Nagios codes
OK, WARNING, CRITICAL, UNKNOWN = 0, 1, 2, 3
DEFAULT_TIMEOUT = 55
DEBUG = False

# OIDs per column
OID_MAP = {
    "name":  "1.3.6.1.2.1.31.1.1.1.1",   # ifName
    "alias": "1.3.6.1.2.1.31.1.1.1.18",  # ifAlias
    "admin": "1.3.6.1.2.1.2.2.1.7",      # ifAdminStatus
    "oper":  "1.3.6.1.2.1.2.2.1.8",      # ifOperStatus
}

def timeout_handler(signum, frame):
    print(f"UNKNOWN - Script timed out after {args.timeout}s")
    sys.exit(UNKNOWN)

def run_snmpbulkwalk(base_oid, host, user, auth_pass, priv_pass, auth_proto, priv_proto):
    cmd = [
        "snmpbulkwalk", "-On", "-v3",
        "-u", user, "-a", auth_proto, "-A", auth_pass,
        "-x", priv_proto, "-X", priv_pass,
        "-l", "authPriv", host, base_oid
    ]
    try:
        out = subprocess.check_output(cmd, stderr=subprocess.DEVNULL, text=True)
        lines = [l.strip() for l in out.splitlines() if l.strip()]
        if DEBUG:
            print(f"\nDEBUG: snmpbulkwalk for {base_oid}:")
            for l in lines: print("  ", l)
        return lines
    except subprocess.CalledProcessError:
        return []

def parse_snmp_output(lines, base_oid):
    result = {}
    for line in lines:
        if "=" not in line:
            continue
        oid_part, value_part = line.split("=", 1)
        idx = oid_part.strip().split(".")[-1]
        value = value_part.strip().split(":", 1)[-1].strip().strip('"')
        result[idx] = value
    return result

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Check SNMPv3 interfaces for up/up")
    parser.add_argument("-H","--host", required=True)
    parser.add_argument("-u","--user", required=True)
    parser.add_argument("-a","--auth_pass", required=True)
    parser.add_argument("-A","--auth_proto", required=True, choices=["MD5","SHA"])
    parser.add_argument("-p","--priv_pass", required=True)
    parser.add_argument("-X","--priv_proto", required=True, choices=["DES","AES"])
    parser.add_argument("-t","--tag", default="[M", help="Match alias tag (default: [M)")
    parser.add_argument("--exclude", nargs="*", default=[
        "EFXS","Voice","ds0","isdn","proppoint","other",
        "lapd","software","em","se","receive","E1","Nu"
    ], help="Exclude these ifName keywords")
    parser.add_argument("--debug", action="store_true")
    parser.add_argument("--all", action="store_true", help="Show all interfaces that match the tag, regardless of status")
    parser.add_argument("--timeout", type=int, default=DEFAULT_TIMEOUT)
    args = parser.parse_args()

    DEBUG = args.debug
    signal.signal(signal.SIGALRM, timeout_handler)
    signal.alarm(args.timeout)

    # fetch each column
    data = {}  # idx → { name, alias, admin, oper }
    for field, base_oid in OID_MAP.items():
        output = run_snmpbulkwalk(base_oid, args.host, args.user,
                                  args.auth_pass, args.priv_pass,
                                  args.auth_proto, args.priv_proto)
        parsed = parse_snmp_output(output, base_oid)
        for idx, val in parsed.items():
            data.setdefault(idx, {})[field] = val

    bad = []
    good = []

    for idx, entry in data.items():
        name  = entry.get("name", "")
        alias = entry.get("alias", "")
        admin = entry.get("admin", "")
        oper  = entry.get("oper", "")

        if any(excl.lower() in name.lower() for excl in args.exclude):
            continue
        if args.tag and args.tag not in alias:
            continue

        line = f"{name} - {alias} - (Admin: {admin}, Oper: {oper})"
        if admin not in ["up", "1", "up(1)"] or oper not in ["up", "1", "up(1)"]:
            bad.append(line)
        else:
            good.append(line)

    if bad:
        print("CRITICAL - Monitored interfaces not in up/up state:")
        print("\n".join("  "+l for l in bad))
        if args.all:
            print("\n".join("  "+l for l in good))    
        sys.exit(CRITICAL)

    if good:
        print("OK - All monitored interfaces are up/up:")
        print("\n".join("  "+l for l in good))
        if args.all:
            print("\n".join("  "+l for l in bad))
        sys.exit(OK)

    print(f"OK - No interface with tag '{args.tag}' found")
    sys.exit(OK)

Simple Unit Test for above code

# Only run tests if script is executed with "test" argument
if __name__ == "__main__" and "test" in sys.argv:
    import unittest
    from unittest.mock import patch

    class TestSNMPCheck(unittest.TestCase):

        @patch("subprocess.check_output")
        def test_interface_up(self, mock_subproc):
            mock_subproc.return_value = "IF-MIB::ifOperStatus.1 = INTEGER: up(1)"
            self.assertEqual(run_snmp_check("localhost", "public"), "up")

        @patch("subprocess.check_output")
        def test_interface_down(self, mock_subproc):
            mock_subproc.return_value = "IF-MIB::ifOperStatus.1 = INTEGER: down(2)"
            self.assertEqual(run_snmp_check("localhost", "public"), "down")

    unittest.main(argv=["first-arg-is-ignored"], exit=False)