Mac Address; Configuring Mtu And Mss - pfSense SG-4860 Quick Start Manual

login name and password or as with static addresses, subnet mask and gateway address.
DHCP is the most common type of interface for home cable modems. One dynamic IP address is issued
from the ISP's DHCP server and will become the public IP address of your network. This address will change
periodically at the discretion of the ISP. Choose DHCP as shown in Figure 8 and proceed to the next section,
MAC Address, MTU and MSS:
Figure 8

MAC address

Figure 9
If replacing an existing firewall, you may want to enter the old firewall's WAN MAC address here, if you can
easily determine it. This avoids common issues involved in switching out firewalls, such as ARP caches, ISPs
locking to single MAC addresses, etc.
If you are not able to enter the MAC address of your current firewall here, the impact is most likely,
insignificant. Power cycle your router and modem and your new MAC address will usually be able to get
online. For some ISPs, you have to call when switching devices, or go through an activation process.

Configuring MTU and MSS

Figure 10
MTU or Maximum Transmission Unit determines the largest protocol data unit that can be passed onwards.
A 1500-byte packet is the largest packet size allowed by Ethernet at the network layer. Leaving this field
blank allows the system to default to 1500-byte packets. PPPoE packets are slightly smaller at 1492-bytes.
We recommend leaving this blank for a basic configuration. MSS and MTU must be set to the same packet
size if you configure them.
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