I've got a Verizon residential cable setup where I placed a personal Linux router directly to the Verizon white box via Ethernet 10Base-1000 and CAT-5 cable. And I need to relocate this Actiontec media gateway router somewhere within my new home subnet and no longer in front of my personal router.
Why would I do such a convoluted setup like this? Because, I like full control of my home network which is full of 802.1X devices, Bro IDS and various other pet projects related to network security.
In order to do this, a complete remapping out the Verizon home network topology is necessary, complete with TCP/UDP, IP and Ethernet layer.
I attached a 10-BaseT Ethernet --> HUB <-- so that WireShark can be captured in its entirety and unchanged from default Verizon setup.
In order to cut out the marketspeak to mere labels for this article, I use the following terms:
- cable router - Actiontec broadband gateway router, provided by Verizon
- personal router - Your beefy brand-new Linux gateway box
I used IP subnets used throughout the home (listed in ingress to egress order):
- 192.168.1.100 - Verizon Settop box, first
- 192.168.1.0/24 - Cable subnet, not changeable by cable router
- 192.168.1.1 - gateway for cable subnet; provided by cable router
- 192.168.6.233 - egress IP of cable router; IP provided by your personal gateway router
- 192.168.6.0/24 - Declared by personal router for home-wide uses.
When a broadband router boots up, it access the following ports to communicate with various Verizon infrastructure servers:
DHCP Client - Verizon HFC network
First the cable router issues a DHCP request to Verizon FiOS DHCP server using the following IP ports:
- Port 67/UDP - egress
- Port 68/UDP - ingress
Then the DHCP-REQUEST options sent by your cable router looks like:
User Datagram Protocol, Src Port: 68, Dst Port: 67
Bootstrap Protocol (Request)
Message type: Boot Request (1)
Hardware type: Ethernet (0x01)
Bootp flags: 0x0000 (Unicast)
0... .... .... .... = Broadcast flag: Unicast
.000 0000 0000 0000 = Reserved flags: 0x0000
Client IP address: 172.32.1.132
Your (client) IP address: 0.0.0.0
Next server IP address: 0.0.0.0
Relay agent IP address: 0.0.0.0
Client MAC address: -f8:e4:XX:XX:XX:XX
Client hardware address padding: 00000000000000000000
Server host name not given
Boot file name not given
Magic cookie: DHCP
Option: (53) DHCP Message Type (Request)
Length: 1
DHCP: Request (3)
Option: (60) Vendor class identifier
Length: 25
Vendor class identifier: Wireless Broadband Router
Option: (12) Host Name
Length: 25
Host Name: Wireless_Broadband_Router
Option: (15) Domain Name
Length: 4
Domain Name: home
Option: (55) Parameter Request List
Length: 18
Parameter Request List Item: (1) Subnet Mask
Parameter Request List Item: (28) Broadcast Address
Parameter Request List Item: (2) Time Offset
Parameter Request List Item: (3) Router
Parameter Request List Item: (15) Domain Name
Parameter Request List Item: (6) Domain Name Server
Parameter Request List Item: (4) Time Server
Parameter Request List Item: (7) Log Server
Parameter Request List Item: (23) Default IP Time-to-Live
Parameter Request List Item: (26) Interface MTU
Parameter Request List Item: (43) Vendor-Specific Informatio
Parameter Request List Item: (50) Requested IP Address
Parameter Request List Item: (51) IP Address Lease Time
Parameter Request List Item: (54) DHCP Server Identifier
Parameter Request List Item: (55) Parameter Request List
Parameter Request List Item: (60) Vendor class identifier
Parameter Request List Item: (61) Client identifier
Parameter Request List Item: (72) Default WWW Server
Option: (255) End
Option End: 255
To deal with that Juniper DHCP server request, my copy of ISC DHCP client configuration for personal router is (also given at GitHub https://github.com/egberts/systemd-dhclient/etc/dhcp/dhclient.conf).
If
your personal gateway router is going to be directly attached to the
ONT (Optical Network Terminator, a white box) like I hooked mine up,
then that gateway's ingress DHCP server is required to serve additional
DHCP specialized options toward the cable router's dhclient.
# Configuration file for /sbin/dhclient.
#
# Customized for Verizon FiOS Juniper DHCP server
#
# This is a sample configuration file for dhclient. See dhclient.conf's
# man page for more information about the syntax of this file
# and a more comprehensive list of the parameters understood by
# dhclient.
#
# Normally, if the DHCP server provides reasonable information and does
# not leave anything out (like the domain name, for example), then
# few changes must be made to this file, if any.
#
send host-name = "Wireless_Broadband_Router";
send domain-name "home";
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, time-servers, log-servers,
default-ip-ttl, dhcp-requested-address, dhcp-lease-time,
dhcp-server-identifier,dhcp-parameter-request-list,
vendor-class-identifier,dhcp-client-identifier,
www-server,
dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
interface-mtu,
ntp-servers;
timeout 60;
retry 60;
reboot 10;
Verizon uses Juniper routers and their DHCP server is ... quirky.
Internet Protocol Version 4, Src: 192.168.6.1, Dst: 255.255.255.255
User Datagram Protocol, Src Port: 67, Dst Port: 68
Bootstrap Protocol (NAK)
Message type: Boot Reply (2)
Hardware type: Ethernet (0x01)
Bootp flags: 0x8000, Broadcast flag (Broadcast)
1... .... .... .... = Broadcast flag: Broadcast
.000 0000 0000 0000 = Reserved flags: 0x0000
Client IP address: 0.0.0.0
Your (client) IP address: 0.0.0.0
Next server IP address: 0.0.0.0
Relay agent IP address: 0.0.0.0
Client MAC address: -f8:e4:XX:XX:XX:XX
Client hardware address padding: 00000000000000000000
Server host name not given
Boot file name not given
Magic cookie: DHCP
Option: (53) DHCP Message Type (NAK)
Length: 1
DHCP: NAK (6)
Option: (54) DHCP Server Identifier
Length: 4
DHCP Server Identifier: 192.168.6.1
Option: (56) Message
Length: 30
Message: requested address is incorrect
Option: (255) End
Option End: 255
Padding: 000000000000000000000000000000000000
DHCP Server - Home Network
For the home network, my DHCP server has the following options.
# shared-network
# subnet
# group
# pool
shared-network "dmz2" {
# deny bootp;
deny duplicates;
# deny booting;
subnet 192.168.6.0 netmask 255.255.255.0
{
# SERVER CONTROL
# authoritative - Tells the DHCP server that it is to act as the one
# true DHCP server for the scopes it's configured to understand, by
# sending out DHCPNAK (DHCP-no-acknowledge) packets to
# misconfigured DHCP clients.
server-identifier 192.168.6.1;
server-name dhcp-server-192-168;
# CLIENT CONTROL
# 'allow unknown-clients' - Tells the DHCP server to assign
# addresses to clients without static host declarations,
# which is almost certainly something you want to do.
#
# Otherwise, only clients you've manually given addresses to
# later in the file will get DHCP assignments.
deny unknown-clients;
ignore client-updates;
# do not use option domain-search in DMZ
# do not use option domain-name in DMZ
# NETWORK COMPONENTS
option log-servers 192.168.6.1;
option subnet-mask 255.255.255.0;
option routers 192.168.6.1;
option ntp-servers 192.168.6.1;
option www-server 192.168.6.1;
option domain-name "verizon.net";
# domain-name-servers may be a standalone DHCP config file
# that gets updated by resolvd daemon and loaded by DHCPD
# via 'include' statement.
#
# Here, it's copied manually from personal gateway's /etc/resolv.conf
option domain-name-servers XXX.XXX.XXX.XXX, XXX.XXX.XXX.XXX;
# log-facility local7;
option broadcast-address 192.168.6.255;
# on release { }
# on expiry { }
on commit {
set clip = binary-to-ascii(10, 8, ".", leased-address);
set clhw = binary-to-ascii(16, 8, ":", substring(hardware, 1, 6));
execute("/usr/local/sbin/dhcpevent", "commit", clip, clhw, host-decl-name);
}
}
}
Of course, I include the following line in the main DHCP server configuration file, usually /etc/dhcp/dhcpd.conf.
include "/etc/dhcp/dhcpd.conf.192.168.6.dmz"
The objective of the above DHCP configuration sub-settings is to emulate the following egress packet from your new DHCP server or your home devices are NOT going to get an IP address.
Ports Used
Then the following Verizon infrastructure servers are consulted next:
- 53/udp DNS (nsphil01.verizon.net, 71.242.0.12)
- 53/udp DNS (nsrest01.verizon.net, ns5.verizon.net, 71.252.0.12)
- 443/tcp HTTPS (cpe-ems2333.verizon.com, 206.46.32.32) Edgecast Server
- 443/tcp HTTPS (cpe-ems2214.verizon.com, 206.46.32.28) Edgecast Server
- 80/tcp HTTP (www.verizon.com, mercuryipg.FALDMDFLD00.fiostv.verizon.net, 71.246.255.44) main web site
- 443/tcp HTTPS (cpe-ems2214.verizon.com, 206.46.32.28) Edgecast Server
- 80/tcp HTTP (71.245.255.44)
- 80/tcp HTTP (www.verizon.com, 71.242.0.12)
Note: Verizon uses CMTS's own time servers via DOCSIS protocol (which is not an NTP protocol) to keep their customer premise equipment's real clock in sync.
