How to choose the router's internet access method? I helped three families get through the differences between PPPoE, dynamic IP, and static IP

help people install routers, eight out of ten get stuck in the first step of the guide: internet access. PPPoE, dynamic IP (some interfaces call it automatic IP acquisition, DHCP), and static IP—these three buttons are all in one, so beginners can only choose with their eyes closed. Last year, my cousin blindly chose a static IP and followed an online tutorial to enter 192.168.1.108. The gateway casually wrote 192.168.1.1, but the whole family was offline all night. In the end, I came to the door and finished work within ten minutes. This article clearly explains the experience I've accumulated from helping three families install broadband: what exactly makes these three methods different, how to determine which one your home is, and what symptoms are caused if you choose wrongly.

clarify one thing first: the three ways to compete are about who will post the IP on the WAN port

router has two openings that care about IP. The LAN port is internal, issuing numbers to the home phone and computer. I covered this thoroughly in my on the router DHCP. The WAN port is external; where its own IP comes from depends on choosing one of the three internet access methods.

three methods, to put it bluntly, three ways to get a number: PPPoE means using your own broadband account and dialing through the carrier to exchange for a new number; Dynamic IP is a manual gesture waiting for the user to send it; whatever the upper-level device sends is used; Static IPs are the most primitive; the address is pre-written on paper, and the four-piece set copies it yourself. Which type of home you have doesn't depend on the router, but on the structure of the network at the previous level.

PPPoE: For families you dial yourself, the account password is the 'Mingmen' (like ours)

My optical cat changed its bridge back then. I wrote an article about the reasons and process whether the optical modem should switch to bridge, but I won't elaborate here. After bridging, the router's WAN port runs PPPoE directly, with the account gd85213xxxx@163.gd string of these words: the password was read by my master on the day of installation. I copied it onto a note and stuck it on the inside of the weak current box cover. It's still there for five years.

The

PPPoE process involves the router packaging the account and password, sending them to the operator's server room authentication device, and after verification, they receive a public IP address. So the characteristics of this company are very obvious: on the router's WAN status page, you see either a public IP or an operator internal network address starting with 100.64, but it definitely doesn't start with 192.168. I've written about this method in the on the router's status page—a single line of IP can be layered.

three points that are prone to failure. First, the letter l and the number 1, and the letter O and the number 0 in the account. My cousin made a mistake by entering a character back then and reported 'authentication failed' for two days; Second, after selecting PPPoE, there's also a connection mode option to choose auto-connect. I've written about the on-demand connection pitfall separately router automatically dials , but the hang-up system is considered idle, causing one to disconnect and one dial; Third, PPPoE's MTU is 1492, not 1500. Don't follow others' tutorials randomly; I calculated this in the of the router MTU.

dynamic IP: The optical modem has already dialed the number, just reach out to connect the router (cousin's house)

cousin's home was installed by a telecom technician. The optical modem is an all-in-one router mode, and the technician set up the entire dialing layer inside the optical modem. With this setup, the router's WAN port can be set to "dynamic IP" or "automatic acquisition," and the network cable connects instantly, with no need to fill in anything.

principle is exactly the same as the DHCP on the LAN port at home, except the roles are reversed: this time the router is the one asking for the number, and the transmitter is the optical modem. Whoever dials is the transmitter—I wrote about the LAN side version in my DHCP article, and the WAN side holds the same way. The detection features are also symmetrical: the router's WAN port status page shows 192.168.1.x or 100.x, which is the internal network number of the optical modem. This indicates the number was sent by the optical modem, and your home is a dynamic IP.

cousin's internet outage that night came about like this. The tutorial she watched said, "Select PPPoE and fill in broadband account," but her broadband account was in the optical modem, and there was no account available on the router layer. She tried three times with the phone number bound to broadband, but authentication failed, and the page showed "Server unresponsive." I switched my internet access to the mobile IP again, saved and restarted for two minutes, and the whole family restored. There's a hidden cost in her situation: the router can't make another layer of PPPoE by itself, because the optical modem in front has already dialed the number, and one broadband can only be authenticated at a time.

renting a place to connect to the landlord's router or a dormitory to a floor switch, the vast majority also use this option. The method is simpler: plug it in and it will automatically get the IP.

Static IP: The address is locked down by network administrators and sent to you (Old Zhang's property broadband)

colleague Lao Zhang's residential complex is built by the property management itself. Back then, the network administrator handed him a piece of paper: IP is 10.0.12.37, mask is 255.255.255.0, gateway is 10.0.12.1, and two DNS files are provided, and he was told to fill them out at home. This is the real scenario where static IPs come into play at home: company intranet, dormitory network, property broadband, and corporate dedicated lines—ordinary home bandwidth is basically useless.

static IP requires a set of four essentials: IP, mask, gateway, DNS—none can be skipped. The most critical issue is the gateway. If you fill it incorrectly, it means the internal network pings and the outer network is completely disconnected, because the router's default route points to a gate that doesn't exist. I have already broken down the manual IP filling account in the of What Gateway Means: masking the network of people and gateway managing exits. Whatever you fill in incorrectly, you get blocked. The reason my cousin randomly chose a static IP and the whole family lost internet was because the IP she entered didn't match the gateway at all, and the default router pointed to an address that no one answered.

here, I want to mention the most common thing beginners can confuse: the static IP on the WAN port and the static IP binding to the printer at home are two different things. The former is the router's external address number, which is entered in the internet access method; The latter is address retention on the LAN side. In DHCP settings, you pin a device to a fixed intranet address. I've written about static IP binding for this operation. One person enters the door, the other inside the house—don't just think of the words 'static IP' together.

don't know which type they are? Three pieces of evidence can be investigated on their own

first piece of evidence: look at the WAN port status page of the old router. As long as your original router can still access the backend, the WAN port IP is clearly visible: a public address or one starting with 100.64 means it's your own dial-up, so select PPPoE; 192.168 or one starting with 10 means your superior is sending a number, so select a dynamic IP. This is the fastest way—a conclusion in one minute.

second piece of evidence: check the light modem. Connect your phone to the fiber modem's WiFi. If you enter 192.168.1.1 or 192.168.2.1 in your browser, you can access the backend. Also, there are connection records on the WAN, and the home WiFi is still sent by the fiber modem, which is usually router mode. Choose a dynamic IP for the router. If it can't enter or it's clearly in a bridge state (I've written about this judgment in the bridge decision section), the router will have to initiate PPPoE itself.

third piece of evidence: ask someone to check the records. The installer's phone number, the work order text message on the day of installation, the receipt for broadband application—any of these can easily ask, "Is your home dialing on the optical modem or the router?" What do you do if you forget what your broadband account looks like? I've written how to check my broadband account password forgotten. That installation work order is worth more than anything.

you filled in the wrong symptoms, take the correct

The

169.254 license plate range is worth noting separately. It is a spaceholder number assigned by the system when the device needs a number but can't be found. Seeing it means no one responds in front of the WAN port—either the cable is blocked or the dial number hasn't been dialed. I also mentioned this account in the of the where 192.168.1.1 can't open, and the mechanism of both scenarios is the same.

By the way, Xiaomi routers also have an 'Internet Access Mode' option in their IPv6 settings. Auto-configuration, Native, and NAT6 are separate things, dealing with how to get the v6 address. It's not the same as the v4 three-choice in this article. Don't mix them up—I wrote about that in the of Xiaomi IPv6 activation.

Wrap up with a clear order: before installing a new router, check the old router's WAN port status page for a conclusion. If you can't get it, confirm whether the optical modem is a router or a bridge; if not, ask a technician to check the work order. After three choices, move the guide. If you really can't get online, just look at the chart above and look for the root cause based on symptoms. If I had glanced at the old router first that night at my cousin's house, ten minutes of work could save an entire night.