The "TTL expired in transit" message occurs when a packet's Time-To-Live (TTL) value reaches zero before reaching its destination. This typically indicates a routing loop where packets circulate endlessly between routers. From your traceroute output, we can see the clear loop pattern between four IPs:

14    60 ms    59 ms    60 ms  xxx.xxx.xxx.2
15    83 ms    81 ms    82 ms  xxx.xxx.xxx.128
16    75 ms    80 ms    81 ms  xxx.xxx.xxx.249
17    81 ms    78 ms    80 ms  xxx.xxx.xxx.250
[loop continues...]

First, let's verify whether this is indeed a routing loop with a simple Python script to analyze traceroute output:

import re
from collections import Counter

def detect_loop(traceroute_log):
    ips = re.findall(r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}', traceroute_log)
    ip_counts = Counter(ips)
    return [ip for ip, count in ip_counts.items() if count > 3]

# Sample usage:
log = """your traceroute output here"""
print("Potential loop IPs:", detect_loop(log))

For network administrators, these steps are essential:

1. Check routing tables on all involved routers (xxx.xxx.xxx.2, .128, .249, .250)
2. Verify BGP/OSPF configurations for inconsistencies
3. Examine firewall rules that might be redirecting traffic
4. Look for asymmetric routing paths

When you can't fix the network immediately, try these programming solutions:

# Python example with increased TTL
import socket

def extended_ping(dest, port=80, ttl=64):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.IPPROTO_IP, socket.IP_TTL, ttl)
    try:
        s.connect((dest, port))
        return True
    except socket.error:
        return False
    finally:
        s.close()

print(extended_ping("target.example.com", ttl=128))

For deeper investigation, use tools like Wireshark or tcpdump to capture packets. Look for these telltale signs:

• Decrementing TTL values with the same source/dest IPs
• Duplicate packet checksums in the loop
• MAC address changes while IPs remain the same

In AWS/Azure/GCP environments, routing loops often occur due to:

# AWS CLI example to check route tables
aws ec2 describe-route-tables \
    --filters "Name=route.destination-cidr-block,Values=10.0.0.0/16" \
    --query "RouteTables[].Routes[]"

Remember to check VPC peering configurations and NAT gateway routes in cloud environments.

---

When you encounter the message TTL expired in transit during a ping attempt, it indicates that the packet's Time-To-Live (TTL) value reached zero before reaching its destination. This typically occurs due to:

• A routing loop in the network path
• Misconfigured firewall rules
• Incorrect routing tables

The repeating IP sequence in your traceroute output suggests a classic routing loop:

14    60 ms    59 ms    60 ms  xxx.xxx.xxx.2
15    83 ms    81 ms    82 ms  xxx.xxx.xxx.128
16    75 ms    80 ms    81 ms  xxx.xxx.xxx.249
17    81 ms    78 ms    80 ms  xxx.xxx.xxx.250
18    82 ms    80 ms    77 ms  xxx.xxx.xxx.2
19   102 ms   101 ms   100 ms  xxx.xxx.xxx.128
...

Here's how to systematically troubleshoot this issue:

1. Verify Network Path

Run traceroute with different TTL values to identify where the loop occurs:

# Linux/macOS
traceroute -m 30 example.com

# Windows
tracert -h 30 example.com

2. Check Routing Tables

Examine the routing tables on the looping devices (if accessible):

# Cisco devices
show ip route

# Linux
ip route show
route -n

3. Packet Capture Analysis

Use tcpdump or Wireshark to analyze traffic at key points:

tcpdump -i eth0 'icmp and (host xxx.xxx.xxx.2 or host xxx.xxx.xxx.128)'

Based on the loop pattern, consider these solutions:

1. Update Routing Configurations

For Cisco devices, you might need to adjust routing metrics:

router ospf 1
 network 192.168.1.0 0.0.0.255 area 0
 distance 110

2. Firewall Rule Adjustments

Check for ICMP blocking rules that might be causing issues:

# iptables example to allow ICMP
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT

3. TTL Value Adjustment

For testing purposes, you can increase the default TTL:

# Linux
sysctl -w net.ipv4.ip_default_ttl=128

# Windows (requires admin)
reg add "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v DefaultTTL /t REG_DWORD /d 128 /f

Here's a Python script to help diagnose the issue:

import subprocess
import re

def check_routing_loop(target):
    try:
        tracert = subprocess.Popen(["tracert", "-h", "30", target], 
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
        out, err = tracert.communicate()
        
        ip_pattern = r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
        ips = re.findall(ip_pattern, out.decode('utf-8'))
        
        # Check for repeating patterns
        for i in range(len(ips)-4):
            if ips[i:i+4] == ips[i+4:i+8]:
                return f"Routing loop detected between {ips[i]} and {ips[i+3]}"
        
        return "No routing loop detected"
    
    except Exception as e:
        return f"Error: {str(e)}"

print(check_routing_loop("example.com"))

If you've tried these steps without success, consider:

• Contacting the network administrators for the looping segments
• Checking with your ISP if the issue occurs outside your local network
• Reviewing BGP peering configurations if this involves multiple autonomous systems