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title	First troubleshooting action

Code Block

language	bash
theme	Midnight
title	traceroute 8.8.8.8 using looback0 as source address

traceroute 8.8.8.8 /vrf inet /interface lo0                            
tracing 8.8.8.8, src=192.168.254.1, vrf=inet, prt=0/33440, tim=1000, tos=0, len=64
1 192.168.254.1 time=0
2 null time=1000
3 null time=1000
4 null time=1000
5 null time=1000
6 null time=1000
7 null time=1000
8 null time=1000
9 null time=1000
10 null time=1000

This confirms the ping failures we observed previously. The output above indicate the packet does not even egress our SOHO router.

What is the inet VRF says ?

Code Block

language	bash
theme	Midnight
title	routes inside VRF inet

show ipv4 route inet                                                   
typ  prefix            metric  iface      hop            time
C    192.168.0.0/24    0/0     sdn1       null           14:30:07
LOC  192.168.0.90/32   0/1     sdn1       null           14:30:07
C    192.168.128.0/24  0/0     sdn999     null           14:30:13
LOC  192.168.128.1/32  0/1     sdn999     null           14:30:13
C    192.168.254.1/32  0/0     loopback0  null           14:30:15

So we have no default routes . Let's configure one then pointing towards ISP BOX gateway:

Code Block

language	bash
theme	Midnight
title	Default route configuration

conf t
ipv4 route inet 0.0.0.0 0.0.0.0 192.168.0.254

Code Block

language	bash
theme	Midnight
title	routes inside VRF inet

show ipv4 route inet                                                   
typ  prefix            metric  iface      hop            time
S    0.0.0.0/0         1/0     sdn1       192.168.0.254  14:30:07
C    192.168.0.0/24    0/0     sdn1       null           14:30:07
LOC  192.168.0.90/32   0/1     sdn1       null           14:30:07
C    192.168.128.0/24  0/0     sdn999     null           14:30:13
LOC  192.168.128.1/32  0/1     sdn999     null           14:30:13
C    192.168.254.1/32  0/0     loopback0  null           14:30:15

So at that point, packet send to 8.8.8.8 are sent to nexthop 192.168.0.254 via sdn1.

Code Block

language	bash
theme	Midnight
title	ping 8.8.8.8

ping 8.8.8.8 /vrf inet /interface lo0                                  
pinging 8.8.8.8, src=192.168.254.1, vrf=inet, cnt=5, len=64, tim=1000, ttl=255, tos=0, sweep=false
.....
result=0%, recv/sent/lost=0/5/5, rtt min/avg/max/total=10000/0/0/5003

But ping is still not not working. Let's figure out what's going on here.

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title	Netwroking Networking environment assumption

As depicted in previous article:

ISP box has a demarcation point set to 192.168.0.254
So ISP box at some point is configured to perform Network Address Translation from 192.168.0.0/24 → ISP public IPv4 interface
When ISP box receives a ICMP ping from 192.168.254.1 which does not match any ISP box NAT rules → Packet is discarded

Therefore in order to have a working seamless networking environment from the ISP box point of view, traffic coming from 192.168.128.0/17 might need to be NAT(ed) into 192.168.0.0/24 network. Let's see If our guess is right.

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