After looking at the script and reading the rest of the posts on that page, I saw that a package could be installed on an offline router. Found tcpdump package and how to install it. Here are the results.
root@OpenWrt:~# reset; \
> NET_IF="wan"; \
> NET_DEV="$(uci get network.${NET_IF}.ifname)"; \
> ifup "${NET_IF}"; sleep 10; \
> tcpdump -v -n -i "${NET_DEV}" udp port 67 or udp port 68 & \
> ip address show dev "${NET_DEV}"; \
> kill -SIGUSR2 "$(pidof udhcpc)"; sleep 10; \
> ip address show dev "${NET_DEV}"; \
> kill -SIGUSR1 "$(pidof udhcpc)"; sleep 10; \
> ip address show dev "${NET_DEV}"; \
> killall tcpdump
7: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
link/ether 6x:xx:xx:xx:xx:x6 brd ff:ff:ff:ff:ff:ff
inet6 fxxx::xxxx:xxxx:xxxx:xxx6/64 scope link
valid_lft forever preferred_lft forever
tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 262144 bytes
7: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
link/ether 6x:xx:xx:xx:xx:x6 brd ff:ff:ff:ff:ff:ff
inet6 fxxx::xxxx:xxxx:xxxx:xxx6/64 scope link
valid_lft forever preferred_lft forever
15:55:26.961124 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x1e79ff8d, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x6xxxxxx3
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
15:55:29.964545 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x1e79ff8d, secs 3, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x6xxxxxx3
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
15:55:32.967998 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x1e79ff8d, secs 6, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x6xxxxxx3
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
15:55:35.969540 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x1e79ff8d, secs 9, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x6xxxxxx3
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
7: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
link/ether 6x:xx:xx:xx:xx:x6 brd ff:ff:ff:ff:ff:ff
inet6 fxxx::xxxx:xxxx:xxxx:xxx6/64 scope link
valid_lft forever preferred_lft forever
4 packets captured
4 packets received by filter
0 packets dropped by kernel
After figuring out how to get tcpdump on the router I ran it from there this time. Saw some ARP requests so let it run a little longer.
Glad I did, as most of the requests contained my public and gateway IPs. However, the last ARP request was unexpected.
I also saw a mac from upstream of my modem. Service providers DHCP server I suspect.
root@OpenWrt:~# tcpdump -i eth0.2 -evn
tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 262144 bytes
16:42:13.963826 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:15.223750 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x76a73d9c, secs 298, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:15.639707 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:42:15.647808 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:16.973377 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:18.227195 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x76a73d9c, secs 301, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:21.230639 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x76a73d9c, secs 304, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:21.658404 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:42:21.666484 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:21.675396 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:28.233842 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:28.753495 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:42:40.563332 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:42:40.853415 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:42.503629 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:44.693716 00:01:5c:6e:3e:46 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has <MY PUBLIC IP> tell <GATEWAY IP>, length 46
16:42:45.460641 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:48.463802 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 3, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:48.888066 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:42:48.896150 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:48.905032 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:51.467310 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 6, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:54.470758 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 9, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:55.522950 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:42:57.473741 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 12, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:42:59.453004 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:00.477181 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 15, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:03.480627 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 18, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:03.643571 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:43:05.370230 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:05.378234 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:06.483739 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 21, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:06.653313 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:43:08.373197 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:08.381219 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:08.948133 00:01:5c:6e:3e:46 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has <MY PUBLIC IP> tell <GATEWAY IP>, length 46
16:43:09.487184 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 24, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:12.490629 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 27, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:14.232707 00:01:5c:6e:3e:46 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has <NOT MY IP 22.xx.xx.xx OR NETWORK> tell <NOT MY GATEWAY 22.xx.xx.1 OR NETWORK>, length 46
16:43:15.232665 00:01:5c:6e:3e:46 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has <NOT MY IP 22.xx.xx.xx OR NETWORK> tell <NOT MY GATEWAY 22.xx.xx.1 OR NETWORK>, length 46
16:43:15.493745 6c:b0:ce:e9:6b:86 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6c:b0:ce:e9:6b:86, length 300, xid 0x43c2fbd7, secs 30, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:15.874686 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:43:15.882774 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:15.891683 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:18.497187 6x:xx:xx:xx:xx:x6 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 6x:xx:xx:xx:xx:x6, length 300, xid 0x43c2fbd7, secs 33, Flags [none]
Client-Ethernet-Address 6x:xx:xx:xx:xx:x6
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 8:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP, Classless-Static-Route
Vendor-Class Option 60, length 12: "udhcp 1.30.1"
Hostname Option 12, length 7: "OpenWrt"
16:43:19.406088 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 102: (hlim 255, next-header ICMPv6 (58) payload length: 48) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 48
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
prefix info option (3), length 32 (4): 2600:6c52:7004:200::/64, Flags [none], valid time 2592000s, pref. time 604800s
16:43:19.414136 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
16:43:19.423087 00:01:5c:6e:3e:46 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 70: (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::201:5cff:fe6e:3e46 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 16
hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 9000s, reachable time 3600000ms, retrans timer 0ms
^C
48 packets captured
48 packets received by filter
0 packets dropped by kernel
For future reference regarding this topic, are IPv6 enteries needed in the diagnostic process? If not I can remove them to shorten the posts.