[initial-PC1] 2026-09-13T14:22:08.639671+00:00
PC1> show
show

NAME   IP/MASK              GATEWAY           MAC                LPORT  RHOST:PORT
VPCS1  192.168.10.10/24     192.168.10.1      00:50:79:66:68:00  20022  127.0.0.1:20023
       fe80::250:79ff:fe66:6800/64

VPCS> 

[initial-PC3] 2026-09-13T14:22:09.100735+00:00
PC3> show
show

NAME   IP/MASK              GATEWAY           MAC                LPORT  RHOST:PORT
VPCS1  192.168.10.20/24     192.168.10.1      00:50:79:66:68:01  20024  127.0.0.1:20025
       fe80::250:79ff:fe66:6801/64

VPCS> 

[initial-R2] 2026-09-13T14:22:09.564686+00:00
R2> ip -4 addr; ip link; ip route; sysctl net.ipv4.ip_forward
ip -4 addr; ip link; ip route; sysctl net.ipv4.ip_forward
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
18: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    inet 192.168.10.1/24 scope global eth0
       valid_lft forever preferred_lft forever
19: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    inet 192.168.20.1/24 scope global eth1
       valid_lft forever preferred_lft forever
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
18: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    link/ether 02:42:d4:39:68:00 brd ff:ff:ff:ff:ff:ff
19: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    link/ether 02:42:d4:39:68:01 brd ff:ff:ff:ff:ff:ff
192.168.10.0/24 dev eth0 scope link  src 192.168.10.1 
192.168.20.0/24 dev eth1 scope link  src 192.168.20.1 
net.ipv4.ip_forward = 1
/ # 
/ # 

[initial-PC2] 2026-09-13T14:22:10.022384+00:00
PC2> show
show

NAME   IP/MASK              GATEWAY           MAC                LPORT  RHOST:PORT
VPCS1  192.168.20.10/24     192.168.20.1      00:50:79:66:68:02  20026  127.0.0.1:20027
       fe80::250:79ff:fe66:6802/64

VPCS> 

[baseline-router] 2026-09-13T14:22:10.484159+00:00
R2> ip link set eth0 up; ip link set eth1 up; sysctl -w net.ipv4.ip_forward=1; ip -4 addr; ip route; sysctl net.ipv4.ip_forward
ip link set eth0 up; ip link set eth1 up; sysctl -w net.ipv4.ip_forward=1; i
p -4 addr; ip route; sysctl net.ipv4.ip_forward
net.ipv4.ip_forward = 1
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
18: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    inet 192.168.10.1/24 scope global eth0
       valid_lft forever preferred_lft forever
19: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    inet 192.168.20.1/24 scope global eth1
       valid_lft forever preferred_lft forever
192.168.10.0/24 dev eth0 scope link  src 192.168.10.1 
192.168.20.0/24 dev eth1 scope link  src 192.168.20.1 
net.ipv4.ip_forward = 1
/ # 
/ # 

[baseline-pc2] 2026-09-13T14:22:12.482181+00:00
PC1> ping 192.168.20.10 -c 3 -i 500 -w 1000
ping 192.168.20.10 -c 3 -i 500 -w 1000

84 bytes from 192.168.20.10 icmp_seq=1 ttl=63 time=1.561 ms
84 bytes from 192.168.20.10 icmp_seq=2 ttl=63 time=1.519 ms
84 bytes from 192.168.20.10 icmp_seq=3 ttl=63 time=1.430 ms

VPCS> 

[baseline-pc3] 2026-09-13T14:22:14.324072+00:00
PC1> ping 192.168.10.20 -c 3 -i 500 -w 1000
ping 192.168.10.20 -c 3 -i 500 -w 1000

84 bytes from 192.168.10.20 icmp_seq=1 ttl=64 time=0.985 ms
84 bytes from 192.168.10.20 icmp_seq=2 ttl=64 time=1.135 ms
84 bytes from 192.168.10.20 icmp_seq=3 ttl=64 time=0.932 ms

VPCS> 

[warm-cache-pc2] 2026-09-13T14:22:49.362315+00:00
PC1> ping 192.168.20.10 -c 3 -i 500 -w 1000
ping 192.168.20.10 -c 3 -i 500 -w 1000

84 bytes from 192.168.20.10 icmp_seq=1 ttl=63 time=1.442 ms
84 bytes from 192.168.20.10 icmp_seq=2 ttl=63 time=1.504 ms
84 bytes from 192.168.20.10 icmp_seq=3 ttl=63 time=1.414 ms

VPCS> 

[cache-before] 2026-09-13T14:22:49.824231+00:00
PC1> show arp
show arp

02:42:d4:39:68:00  192.168.10.1 expires in 85 seconds 
00:50:79:66:68:01  192.168.10.20 expires in 81 seconds 

VPCS> 

[fault-router-down] 2026-09-13T14:22:50.346705+00:00
R2> ip link set eth0 down; ip link show eth0
ip link set eth0 down; ip link show eth0
18: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel state DOWN qlen 1000
    link/ether 02:42:d4:39:68:00 brd ff:ff:ff:ff:ff:ff
/ # 
/ # 

[fault-pc2] 2026-09-13T14:22:55.589352+00:00
PC1> ping 192.168.20.10 -c 3 -i 500 -w 1000
ping 192.168.20.10 -c 3 -i 500 -w 1000

192.168.20.10 icmp_seq=1 timeout
192.168.20.10 icmp_seq=2 timeout
192.168.20.10 icmp_seq=3 timeout

VPCS> 

[cache-after-fault] 2026-09-13T14:22:56.048658+00:00
PC1> show arp
show arp

02:42:d4:39:68:00  192.168.10.1 expires in 79 seconds 
00:50:79:66:68:01  192.168.10.20 expires in 75 seconds 

VPCS> 

[recovery-router] 2026-09-13T14:22:56.511883+00:00
R2> ip link set eth0 up; ip link set eth1 up; sysctl -w net.ipv4.ip_forward=1; ip -4 addr; ip route; sysctl net.ipv4.ip_forward
ip link set eth0 up; ip link set eth1 up; sysctl -w net.ipv4.ip_forward=1; i
p -4 addr; ip route; sysctl net.ipv4.ip_forward
net.ipv4.ip_forward = 1
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
18: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    inet 192.168.10.1/24 scope global eth0
       valid_lft forever preferred_lft forever
19: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    inet 192.168.20.1/24 scope global eth1
       valid_lft forever preferred_lft forever
192.168.10.0/24 dev eth0 scope link  src 192.168.10.1 
192.168.20.0/24 dev eth1 scope link  src 192.168.20.1 
net.ipv4.ip_forward = 1
/ # 
/ # 

[recovery-pc2] 2026-09-13T14:22:58.496595+00:00
PC1> ping 192.168.20.10 -c 3 -i 500 -w 1000
ping 192.168.20.10 -c 3 -i 500 -w 1000

84 bytes from 192.168.20.10 icmp_seq=1 ttl=63 time=1.731 ms
84 bytes from 192.168.20.10 icmp_seq=2 ttl=63 time=1.308 ms
84 bytes from 192.168.20.10 icmp_seq=3 ttl=63 time=1.298 ms

VPCS> 

[recovery-pc3] 2026-09-13T14:23:00.493412+00:00
PC1> ping 192.168.10.20 -c 3 -i 500 -w 1000
ping 192.168.10.20 -c 3 -i 500 -w 1000

84 bytes from 192.168.10.20 icmp_seq=1 ttl=64 time=0.868 ms
84 bytes from 192.168.10.20 icmp_seq=2 ttl=64 time=0.889 ms
84 bytes from 192.168.10.20 icmp_seq=3 ttl=64 time=1.181 ms

VPCS> 