Block Specific Numbers or Patterns

Exact Match:
+15551234567         → Block this specific number

Starts With:
+44                  → Block all UK numbers
+1900                → Block all 900 premium numbers

Contains:
*1234*               → Block any number containing 1234

Wildcard:
+1555123____         → Block range +1555123-0000 to +1555123-9999

Advanced Pattern Matching Techniques

Wildcard Patterns:

Single Digit (_):

Pattern: +1555123___0
Matches: +15551230000 to +15551239990 (every 10th number)
Use Case: Block number range with pattern

Multiple Digits (*):

Pattern: +1*5551234567
Matches: +15551234567, +115551234567, +12225551234567
Use Case: Match regardless of prefix variations

Area Code Blocking:

Pattern: +1900*
Matches: All US 900 premium numbers
Pattern: +1976*
Matches: All US 976 pay-per-call numbers

Country Code Blocking:

Pattern: +44*
Matches: All UK numbers
Pattern: +86*
Matches: All China numbers
Pattern: +234*
Matches: All Nigeria numbers (high fraud risk)

Regex Patterns (Advanced):

International Except North America:

Regex: ^(?!\+1)[+][0-9]+$
Matches: Any international number except +1 (US/Canada)
Use Case: Block all international except North America

Premium Rate Numbers:

Regex: ^(\+1900|\+1976|\+1809)
Matches: US premium and Caribbean high-cost numbers
Use Case: Prevent expensive toll fraud

Anonymous/Private Callers:

Pattern: Anonymous
Or: Private
Or: Restricted
Matches: Calls with hidden caller ID
Use Case: Block callers hiding their identity

Pre-Built Blocking Scenarios

Scenario 1: Block All International

Rule Name: Block-All-International
Pattern: ^(?!\+1)[+][0-9]+$
Match Type: Regex
Action: Reject Call
Use Case: Domestic-only business

Scenario 2: Block Premium Numbers

Rule 1: Block-900-Numbers
Pattern: +1900*
Action: Play message "Premium numbers not allowed"

Rule 2: Block-976-Numbers
Pattern: +1976*
Action: Play message "Pay-per-call blocked"

Scenario 3: Block High-Fraud Countries

Rule 1: Block-Nigeria
Pattern: +234*
Action: Reject

Rule 2: Block-Somalia
Pattern: +252*
Action: Reject

Rule 3: Block-Cuba
Pattern: +53*
Action: Reject

Scenario 4: Block Specific Spam Caller

Rule Name: Block-Spam-Caller-ID
Pattern: +15551234567
Match Type: Exact
Action: Reject
Notes: Reported spam caller, multiple complaints

Scenario 5: Block Number Range

Rule Name: Block-Competitor-Numbers
Pattern: +1555123*
Action: Reject
Use Case: Block known competitor's number range

Scenario 6: Block Anonymous Callers

Rule Name: Block-Hidden-CallerID
Pattern: Anonymous|Private|Restricted|Unknown
Match Type: Regex
Action: Play message "Please disable caller ID blocking"
Use Case: Require caller ID for business calls

Bulk Import Blocking Rules

rule_name,pattern,match_type,action,enabled
Block-UK-Numbers,+44*,starts_with,reject,true
Block-Premium-900,+1900*,starts_with,reject,true
Block-Spam-1,+15551234567,exact,reject,true
Block-International,^(?!\+1)[+][0-9]+$,regex,play_message,true

Pre-Made Lists (Available):

• Spam Database: 1000+ known spam numbers
• Toll Fraud Countries: High-risk international codes
• Premium Numbers: All US premium rate prefixes
• Anonymous Patterns: Various hidden caller ID formats

Allow Only Specific Numbers

Exact Match:
+15551234567         → Allow only this number

Starts With:
+1555*               → Allow entire area code 555
+1                   → Allow all North America

Contains:
*1234*               → Allow any number with 1234

Wildcard:
+44207_______        → Allow London area code range

Whitelist-Only Operation

What is Exclusive Mode? When enabled, ONLY numbers on the whitelist can call through the trunk. Everything else is automatically blocked.

Use Cases:

High-Security Environment:

Scenario: Government office, only allow approved numbers
Configuration:
- Enable Exclusive Whitelist Mode
- Add all approved government numbers
- Add emergency services
- Add key personnel mobile numbers
Result: Zero spam, complete control

Private Hotline:

Scenario: Support hotline for VIP clients only
Configuration:
- Enable Exclusive Mode on dedicated trunk
- Add VIP client numbers
- Regular customers use different trunk
Result: VIP-only access

Internal Testing:

Scenario: Test trunk before production
Configuration:
- Enable Exclusive Mode
- Add only test team numbers
- Perform testing without risk
- Disable Exclusive Mode when ready
Result: Controlled testing environment

Emergency Contact System:

Scenario: After-hours emergency line
Configuration:
- Separate trunk for emergencies
- Whitelist on-call staff only
- Block all other callers
Result: True emergency calls only

Common Whitelist Patterns

VIP Client Allowlist:

Client 1: +15551234567      (exact)
Client 2: +15559876543      (exact)
Client 3 Mobile: +15551111111    (exact)
Notes: Manual entry of each VIP number

Partner Company Range:

Pattern: +1555123*
Matches: All numbers from partner's number range
Use Case: Allow entire partner organization

Geographic Allow (Local Only):

Pattern: +1555*
Matches: All local area code 555
Use Case: Local-only business, block long distance

Mobile Numbers Only:

Regex: ^(\+1[2-9]\d{2}[2-9]\d{6})$
Matches: Valid US mobile numbers
Use Case: Mobile-only access (no landlines)

International HQ Locations:

Rule 1: Allow-US-HQ
Pattern: +1555*

Rule 2: Allow-UK-HQ  
Pattern: +442071*

Rule 3: Allow-Singapore-HQ
Pattern: +656*

Use Case: Multi-location company, only allow company sites

Blacklist + Whitelist Interactions

Rule Precedence:

1. Whitelist evaluated first (highest priority)
2. Blacklist evaluated second
3. Default allow if no matches

Scenario 1: VIP Bypass Spam Block

Blacklist: +1555123*  (block entire range - spam source)
Whitelist: +15551234567  (but allow this specific VIP)
Result: +15551234567 connects (whitelist wins)
        +15551234568 blocked (blacklist applies)

Scenario 2: Allow Region, Block Specific

Whitelist: +1555*  (allow area code)
Blacklist: +15551234567  (block known problem number)
Result: Blacklist has no effect (whitelist allows everything matching +1555*)

Scenario 3: International with Exceptions

Blacklist: +44*  (block all UK)
Whitelist: +442071234567  (allow UK office)
Result: UK office can call, other UK numbers blocked

Best Practice Combinations:

Spam Protection + VIP Access:

1. Import spam database to blacklist
2. Add VIP customers to whitelist
3. VIPs always connect, spam always blocked

Geographic + Exception:

1. Blacklist all international (+^(?!\+1))
2. Whitelist specific international partners
3. Domestic unrestricted, international selective

Time-Based + Whitelist:

1. After hours, enable exclusive whitelist mode
2. Only on-call staff numbers whitelisted
3. During business hours, disable exclusive mode
4. Normal operation with blacklist only

Wildcard Pattern Reference

Single Digit Wildcard (_):

Pattern: +1555123___0
Matches:
  ✓ +15551230000
  ✓ +15551231230
  ✓ +15551239990
  ✗ +15551230001 (last digit not 0)
  ✗ +155512300 (too short)

Multiple Digit Wildcard (*):

Pattern: +1555*
Matches:
  ✓ +1555
  ✓ +15551234567
  ✓ +15559999999999
  ✗ +1556 (doesn't start with +1555)

Start of String (^):

Pattern: ^+1555
Matches: Numbers starting with +1555
Must be at beginning of number

End of String ($):

Pattern: 4567$
Matches: Numbers ending with 4567
Must be at end of number

Character Class ([...]):

Pattern: +1555[0-5]*
Matches: +1555 followed by digits 0-5
Example: +15550123, +15555555
Not: +15556789 (6 not in class)

Negation ([^...]):

Pattern: +1555[^09]*
Matches: +1555 but NOT followed by 0 or 9
Example: +15551234, +15558888
Not: +15550123, +15559999

Regular Expression Patterns

Block International (Except US/Canada):

Regex: ^(?!\+1)[+][0-9]+$
Explanation:
  ^         = start of string
  (?!\+1)   = negative lookahead, not +1
  [+]       = must start with +
  [0-9]+    = one or more digits
  $         = end of string

Premium Rate Numbers (US):

Regex: ^(\+1900|\+1976|\+1809|\+1284|\+1649|\+1242)
Matches:
  900: premium numbers
  976: pay-per-call
  809: Caribbean premium
  284, 649, 242: high-cost Caribbean

Toll Fraud High-Risk Countries:

Regex: ^(\+234|\+252|\+225|\+223|\+233|\+254)
Matches:
  234: Nigeria
  252: Somalia  
  225: Ivory Coast
  223: Mali
  233: Ghana
  254: Kenya

Mobile Numbers Only (US):

Regex: ^(\+1[2-9]\d{2}[2-9]\d{6})$
Explanation:
  \+1       = country code
  [2-9]     = area code first digit (2-9)
  \d{2}     = area code remaining digits
  [2-9]     = exchange first digit (2-9)
  \d{6}     = remaining digits

Anonymous Caller Variations:

Regex: ^(Anonymous|Private|Restricted|Unknown|Unavailable|Blocked)$
Matches: Common hidden caller ID names (case-sensitive)

Specific Area Codes:

Regex: ^(\+1(555|800|888|877|866|855|844|833))
Matches: Toll-free and test area codes

International Format Validation:

Regex: ^\+[1-9]\d{1,14}$
Validates: Proper E.164 format
  Must start with +
  Country code 1-999
  Total 1-15 digits (after +)

Pattern Testing Tool

+15551234567    → ✓ Match
+15559999999    → ✓ Match
+15561234567    → ✗ No match
+4415551234567  → ✗ No match

Testing Best Practices:

1. Test Both Positive and Negative:

   • Numbers that SHOULD match
   • Numbers that SHOULD NOT match

2. Test Edge Cases:

   • Shortest possible match
   • Longest possible match
   • Numbers just outside pattern

3. Test Real-World Numbers:

   • Use actual numbers from call logs
   • Include various formats
   • Test international variations

4. Performance Testing:

   • Test with 1000+ numbers
   • Measure pattern evaluation time
   • Compare wildcard vs regex speed

Pattern Matching Performance

Performance Rankings (fastest to slowest):

1. Exact Match (fastest):

Pattern: +15551234567
Speed: 0.001ms per match
Use Case: Block specific known numbers

2. Prefix Match (very fast):

Pattern: +1555*
Speed: 0.002ms per match  
Use Case: Block area codes, country codes

3. Simple Wildcard (fast):

Pattern: +1555123____
Speed: 0.005ms per match
Use Case: Number ranges with pattern

4. Simple Regex (moderate):

Pattern: ^(\+1900|\+1976)
Speed: 0.02ms per match
Use Case: Multiple specific prefixes

5. Complex Regex (slowest):

Pattern: ^(?!\+1)[+][0-9]+$
Speed: 0.1ms per match
Use Case: Complex logic, multiple conditions

Performance Impact:

Low Volume (< 100 calls/hour):

• Any pattern type acceptable
• Regex complexity doesn't matter
• Prioritize correctness over speed

Medium Volume (100-1000 calls/hour):

• Prefer wildcards over regex
• Limit complex regex patterns
• Monitor CPU usage

High Volume (> 1000 calls/hour):

• Use exact match or prefix match only
• Avoid complex regex
• Consider hardware upgrades
• Monitor performance metrics

Optimization Tips:

1. Sort by Specificity: Most specific rules first

   Order:
   1. Exact match rules (fastest exit)
   2. Prefix match rules
   3. Wildcard rules
   4. Regex rules (slowest)

2. Combine Similar Patterns:

   Instead of:
   +1900*, +1976*, +1809*
   
   Use:
   ^(\+1900|\+1976|\+1809)
   (One regex instead of three rules)

3. Use Caching: System caches recent pattern matches

4. Limit Rule Count: < 100 rules for best performance

Export Blocking/Allowing Rules

rule_name,pattern,match_type,action,enabled,notes
Block-International,^(?!\+1)[+][0-9]+$,regex,reject,true,Block all except US/Canada
Block-Premium,+1900*,starts_with,reject,true,Premium rate numbers
Allow-VIP-1,+15551234567,exact,allow,true,VIP Client Alpha Corp

[
  {
    "rule_name": "Block-International",
    "pattern": "^(?!\\+1)[+][0-9]+$",
    "match_type": "regex",
    "action": "reject",
    "enabled": true,
    "notes": "Block all except US/Canada"
  }
]

<rules>
  <rule>
    <name>Block-International</name>
    <pattern>^(?!\+1)[+][0-9]+$</pattern>
    <type>regex</type>
    <action>reject</action>
  </rule>
</rules>

Import Blocking Rules

Sharing Rules Between Trunks/Systems

Same PBX, Different Trunk:

1. Export from Trunk A
2. Import to Trunk B
3. Adjust trunk-specific patterns if needed

Different PBX System:

1. Export from source PBX
2. Review/adjust for compatibility
3. Import to destination PBX
4. Test thoroughly

Team/Community Sharing:

• Share spam databases
• Collaborate on fraud prevention
• Standardize across organization
• Version control rule sets

Pre-Made Rule Sets (Available):

• Global Spam Database: 10,000+ spam numbers
• Toll Fraud Protection: High-risk country codes
• Premium Block: All premium rate patterns
• Anonymous Block: Hidden caller ID variations

Rule Set Version Control

Why Version Control?:

• Track changes over time
• Roll back problematic rules
• Audit who changed what
• Document reasons for rules

Versioning Strategy:

Version 1.0: Initial deployment
  - Basic spam blocking
  - 50 rules

Version 1.1: Added toll fraud protection
  - High-risk countries
  - Premium numbers
  - 125 rules

Version 1.2: VIP whitelist
  - Added key client whitelist
  - Exclusive mode for after-hours
  - 150 rules

Change Log Example:

2024-11-21 - John Smith
  Added: Block Nigeria (+234*)
  Reason: 10 toll fraud attempts detected
  
2024-11-15 - Jane Doe
  Added: Allow VIP Client (+15551234567)
  Reason: VIP complained about accidental block

2024-11-10 - Bob Johnson
  Removed: Block UK numbers (too broad)
  Added: Block specific UK spam range (+441234*)
  Reason: Blocking legitimate UK clients

Backup Strategy:

• Daily automatic exports
• Store in version control (Git)
• Keep 90 days of history
• Document major changes

Legitimate Calls Being Blocked

Symptoms:

• Important clients can't reach you
• Complaints about blocked calls
• Missing expected calls

Diagnostic Steps:

1. Check Call Logs:

   • Review blocked calls list
   • Identify which rule blocked call
   • Verify if block was intentional

2. Review Pattern:

   • Is pattern too broad?
   • Example: +1555* blocks entire area code
   • Narrow pattern to specific problem numbers

3. Check Precedence:

   • Is blacklist overriding whitelist?
   • Add specific number to whitelist
   • Whitelist should take precedence

4. Test Pattern:

   • Use pattern tester with blocked number
   • Verify pattern matches as expected
   • Adjust pattern if needed

Solutions:

Add to Whitelist:

Add: +15551234567 (specific client)
Priority: High
Result: Always allowed, bypasses blacklist

Narrow Pattern:

Before: +1555* (blocks entire area code)
After: +15559* (blocks only 555-9xxx range)
Result: Other numbers in area code work

Disable Rule Temporarily:

Disable problematic rule
Test if calls connect
Refine rule pattern
Re-enable with new pattern

Rule Not Blocking Expected Numbers

Symptoms:

• Spam calls still getting through
• Pattern doesn't match test numbers
• Rule appears enabled but not working

Diagnostic Steps:

1. Verify Rule Enabled:

   • Check rule status (enabled/disabled)
   • Verify correct trunk assigned
   • Confirm rule priority

2. Test Pattern:

   • Use pattern tester
   • Enter actual spam number
   • See if pattern matches

3. Check Number Format:

   • How does provider send caller ID?
   • E.164 format (+15551234567)?
   • Local format (5551234567)?
   • Pattern must match actual format received

4. Review Rule Type:

   • Exact vs starts_with vs regex
   • Correct type for your pattern?

Common Issues:

Format Mismatch:

Rule pattern: +15551234567
Provider sends: 5551234567
Result: No match (missing +1)

Solution: Add second rule for local format
  Or use number normalization

Wildcard Syntax Error:

Incorrect: +1555*123
Correct: +1555123* (* at end for wildcard)

Regex Escape Characters:

Incorrect: +1 (space and unescaped +)
Correct: \+1 (escaped + for regex)

Case Sensitivity:

Pattern: anonymous
Caller ID: Anonymous
Result: No match (case-sensitive)

Solution: Use regex with case-insensitive flag
  Or: (anonymous|Anonymous|ANONYMOUS)

Slow Call Setup Due to Pattern Matching

Symptoms:

• Increased call setup time
• High CPU usage during calls
• System slowdown

Diagnostic Steps:

1. Check Rule Count:

   • How many rules active?
   • Over 100 rules can impact performance
   • Consider consolidation

2. Identify Slow Patterns:

   • Complex regex patterns slow
   • Monitor pattern evaluation time
   • Optimize or replace

3. Check Rule Order:

   • Most common matches first?
   • Exact matches before regex
   • Optimize rule priority

4. System Resources:

   • CPU usage during call setup
   • Memory usage
   • Trunk call volume

Solutions:

Consolidate Rules:

Before (3 rules):
  +1900*
  +1976*  
  +1809*

After (1 rule):
  ^(\+1900|\+1976|\+1809)

Result: Faster evaluation

Replace Regex with Wildcards:

Before: ^(\+1555[0-9]{7})$
After: +1555*

Result: 10x faster matching

Reorder Rules:

Priority order:
1. Exact matches (fastest)
2. Prefix wildcards
3. Complex wildcards
4. Simple regex
5. Complex regex (slowest)

Enable Caching:

Cache recent pattern matches
Reduces repeated evaluation
Significant improvement for repeat callers

Whitelisted Numbers Still Blocked

Symptoms:

• Whitelisted number blocked
• Whitelist appears enabled
• No apparent reason for block

Diagnostic Steps:

1. Verify Whitelist Entry:

   • Check pattern matches exactly
   • Verify enabled status
   • Check trunk assignment

2. Check Exclusive Mode:

   • Is exclusive mode enabled elsewhere?
   • Time-based rules active?
   • Conflicting configuration?

3. Review Call Logs:

   • Which rule blocked call?
   • Was it blacklist or other rule?
   • Error message details

4. Test Pattern:

   • Use pattern tester
   • Verify whitelist pattern matches
   • Check for typos

Common Issues:

Pattern Typo:

Whitelist: +15551234567
Caller: +15551234568
Result: No match (last digit different)

Precedence Issue:

Some systems: blacklist overrides whitelist
Check: precedence settings
Fix: Ensure whitelist has priority

Multiple Trunk Rules:

Whitelist on Trunk A
Call comes in on Trunk B
Result: Whitelist doesn't apply

Solution: Add whitelist to correct trunk

Time-Based Rules:

Whitelist only active during business hours
Call after hours gets blocked by exclusive mode
Solution: Ensure whitelist applies 24/7 or adjust time rules

System-Wide Block:

Number blocked at system level (above trunk level)
Trunk whitelist can't override
Solution: Remove from system blacklist

Blocking Spam and Robocalls

Strategy:

1. Import community spam database
2. Block anonymous callers
3. Block frequent spam area codes
4. Whitelist known contacts

Implementation:

Rule 1: Block-Spam-Database
Pattern: Import from spam list
Action: Reject
Count: 5,000+ numbers

Rule 2: Block-Anonymous
Pattern: ^(Anonymous|Private|Restricted)$
Action: Play message "Please enable caller ID"

Rule 3: Block-Spam-Area-Codes
Pattern: ^(\+1564|\+1855844)
Action: Reject
Reason: Known spam origin codes

Whitelist: Import customer database
Pattern: Customer phone numbers
Priority: High

Results:

• 95% reduction in spam calls
• No customer complaints
• Minimal false positives
• Improved staff productivity

Preventing International Toll Fraud

Threat: Hackers compromise PBX, make expensive international calls, resulting in thousands in fraud charges.

Protection Strategy:

Block High-Risk Countries:

Block: +234* (Nigeria - #1 fraud source)
Block: +252* (Somalia)
Block: +225* (Ivory Coast)  
Block: +223* (Mali)
Block: +233* (Ghana)
Block: +254* (Kenya)
Block: +53* (Cuba)
Block: +95* (Myanmar)

Block Premium Numbers:

Block: +1900* (US premium)
Block: +1976* (US pay-per-call)
Block: +1809* (Caribbean premium)
Block: +1284* (British Virgin Islands)
Block: +1649* (Turks and Caicos)

Allow Only Business Regions:

Whitelist Exclusive Mode (after hours)
Allow: +1* (US/Canada)
Allow: +44* (UK office)
Allow: +61* (Australia office)
Block: Everything else

Monitor and Alert:

• Alert on blocked international calls
• Daily reports of blocking activity
• Immediate notification of fraud attempts
• Review patterns weekly

Results:

• Zero toll fraud incidents
• $50,000+ potential fraud prevented
• Peace of mind

Geographic Call Restrictions

Scenario 1: Domestic Only Business

Business: Local retail store
Customers: US only
Goal: Block all international

Configuration:
Block: ^(?!\+1)[+][0-9]+$
Allow: +1*
Result: US/Canada only

Scenario 2: Multi-National with Exceptions

Business: International company
Offices: US, UK, Singapore
Goal: Block all except office regions

Configuration:
Exclusive Whitelist Mode
Allow: +1* (US/Canada)
Allow: +44* (UK)
Allow: +65* (Singapore)
Block: Everything else
Result: Three regions only

Scenario 3: Avoid High-Cost Regions

Business: Cost-conscious startup
Goal: Block expensive international

Configuration:
Allow: +1* (local)
Block: All international except:
Allow: +44* (UK - business partner)
Result: Domestic + selective international

Scenario 4: State/Province Restrictions

Business: State-licensed service
License: California only
Goal: California callers only

Configuration:
Allow patterns for CA area codes:
  +1209*, +1213*, +1310*, +1323*,
  +1341*, +1408*, +1415*, +1424*,
  +1442*, +1510*, +1530*, +1559*,
  +1562*, +1619*, +1626*, +1628*,
  +1650*, +1657*, +1661*, +1669*,
  +1707*, +1714*, +1747*, +1760*,
  +1805*, +1818*, +1820*, +1831*,
  +1858*, +1909*, +1916*, +1925*,
  +1949*, +1951*
Exclusive Mode: Yes
Result: California only

VIP and Priority Caller Management

Scenario 1: VIP Bypass Everything

Business: High-end service
VIP Clients: Top 10 accounts
Goal: VIPs never blocked

Configuration:
Blacklist: Aggressive spam blocking
Whitelist (High Priority):
  +15551111111 (VIP Client A)
  +15552222222 (VIP Client B)
  +15553333333 (VIP Client C)
  ...
Result: VIPs always connect, spam blocked

Scenario 2: After-Hours Emergency

Business: Medical practice
After Hours: Emergencies only
Goal: Only doctors and on-call staff

Configuration:
Time-Based Rule (6pm-8am):
  Enable Exclusive Whitelist Mode
  Whitelist:
    +15551234567 (Dr. Smith)
    +15559876543 (Dr. Jones)
    +15551111111 (On-call service)
Result: After-hours, only authorized callers

Scenario 3: Executive Direct Line

Business: Corporation
Executive: CEO direct line
Goal: Board members and C-suite only

Configuration:
Trunk: CEO-Direct-Line
Exclusive Whitelist: Enabled 24/7
Whitelist:
  +15551111111 (CFO)
  +15552222222 (CTO)
  +15553333333 (Board Chair)
  ... (board members)
Result: Truly private direct line

Scenario 4: Support VIP Queue

Business: SaaS company
VIP Support: Dedicated trunk
Goal: VIP customers skip queue

Configuration:
Trunk: VIP-Support
Whitelist: VIP customer numbers
Routing: Direct to VIP support team
Result: VIPs bypass normal support queue