31
votes
Accepted
I am confused about the way a common home router works: Shouldn’t the MAC addresses be enough to forward the information to the correct destination?
On the router, I forward the port 80 (external) to the port 80 (internal) of (instead of the local IP) the MAC address of the PC.
I know this is not how it works, the question is why it wasn't ...
- 437k
27
votes
How does the airconditioner app on my phone access my aircon controller through my router?
Many smart home devices make their own outgoing connection to a server run by the vendor, and the vendor's smartphone app also logs into your account on the vendor's server, and the server takes care ...
- 103k
20
votes
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Netgear DGND3800B limiting FTTH speed to 300Mbps
In case 3, you are not testing the router at all – the PCs are connected only through a Gigabit Ethernet switch built into the router. The switch is capable of independently forwarding packets (or ...
- 437k
14
votes
Is 2.4 GHz Wi-Fi band shared across routers?
In broad, non-technical terms, it is congested because "everybody is talking at the same time".
Wifi, just like human conversation, isn't really directional, it spreads out around you, ...
- 48.7k
12
votes
Accepted
wifi router not getting a signal from network switch
Unifi U6 (which is not a router)1 is a PoE-powered device – it receives DC power through the same Ethernet cable as it uses for data. Most likely the other end of the wall outlet goes either into a ...
- 437k
10
votes
How does the airconditioner app on my phone access my aircon controller through my router?
Without going into technical detail - which a) I'm not very good at & b) is likely to be different depending on app & IOT device…
Both connect to a 'central server' out there on the interwebz, ...
- 48.7k
9
votes
I am confused about the way a common home router works: Shouldn’t the MAC addresses be enough to forward the information to the correct destination?
The reason is actually really simple: So that the hosts don't have to know or care whether they are behind a NAT layer.
Consider a student with a laptop. When he carries it to the university, that ...
- 7,214
8
votes
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Ethernet WAN - safety hazard?
Some homes have in-wall telephone wiring with "RJ-45" 8-position modular jacks, with the center pair (pins 4 & 5) wired as a phone line. You can safely connect a typical RJ-11 (6P2C ...
- 103k
7
votes
Is 2.4 GHz Wi-Fi band shared across routers?
As an addition to nice Tetsujin analogy, note that the same sharing of spectrum happens with both 2.4 GHz and 5 GHz.
However, as opposed to humans talking, there is actually more than one frequency in ...
- 2,646
7
votes
Accepted
Can I use my Wi-Fi Router as a DHCP server for the rest of my network if I connect a switch into the ISP modem and connect items into the switch?
Its useful to look at what we need here first and the topology I am suggesting. DHCP can run anywhere on the network, and its just a service that sets up IPs within the network. You can even run a ...
- 128k
7
votes
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External access to NAS behind router - security concerns?
Does doing this pose a realistic security concern? Or only, if certain things are (not) done - can it be made reasonably slim? E.g. say the Fritzbox offers access via username + password: if both ...
- 437k
7
votes
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Can I connect 2 Ethernet cables from the same router to a bridge mode router?
Does connecting another cable to the bridged mode router will help the internet speed by any way? Like the idea of dual NICs.
In your setup – no, likely not. (It's the same with dual NICs too.)
The ...
- 437k
6
votes
Accepted
Packet Drop When BGP Withdrawal
The withdrawal of the route from your router is only the beginning of the process which updates routing tables across whole Internet, not the end of it. Why do you think it is going to happen ...
- 1,198
6
votes
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Why does a running ping process keep working during an internet outage, but restarting ping doesn't?
How is this possible? It apparently seems like "active ping sessions" aren't affected by my outage. But with ping using ICMP on layer 3, I don't get why there is a difference between keeping ...
- 437k
5
votes
I am confused about the way a common home router works: Shouldn’t the MAC addresses be enough to forward the information to the correct destination?
TCP/IP uses IP for routing traffic. It's there in the name.
If you were to use MAC addresses then you wouldn't be using TCP/IP and at that point the router would need to do even more work to take in ...
- 90.8k
5
votes
What do AX1800, AX3000, etc. mean within Wifi 6 (802.11ax)?
The numbers indicate the cumulative maximum theoretical bandwidth for all the devices in the package.
The Bands Available and their maximum theoretical bandwidths are
2.4 Ghz: 480 Mbps
5 Ghz: 1300 ...
5
votes
I am confused about the way a common home router works: Shouldn’t the MAC addresses be enough to forward the information to the correct destination?
The internet wasn't really designed to have "private addresses" in the first place. A device that's connected to the internet is expected to have an internet address (i.e. a public IP ...
- 1,273
5
votes
Accepted
How to utilize multiple ethernet ports in an apartment with a network box, switch, and router?
What you will do is take the cable coming from the main line from the internet provider that will be connected to the WAN port of the router.
Then a cable will go from one of the router's LAN ports to ...
- 10.2k
4
votes
Accepted
Can the network administrator know if a port is connected to a router or a laptop?
Probably. The router will have a MAC address, and MAC addresses are allocated by manufacturer (and possibly by product type as well). If your network admins look at the switch or router at their end, ...
- 4,503
4
votes
Packet Drop When BGP Withdrawal
when we do this, we get a packet drop for about 2-3 seconds (I tried pinging it and it shows TTL Expire).
Typically it means one of the routers involved has already processed the update, but another ...
- 437k
4
votes
How routing works on Internet
So your question is awfully broad as stated, so I'll barely scratch the surface, but I think the thing you are missing is that the route is not decided in advance (in fact multiple packets in a ...
- 35.5k
4
votes
Why do I get better bandwidth using WiFi than Ethernet using Teams
When networking pros recommend using Ethernet for better results than Wi-Fi, they mean Ethernet all the way from your client device to your main router, with no Wi-Fi, MoCA, or powerline hops along ...
- 103k
4
votes
Accepted
How routers deal with only one external IP?
The following is a very basic explanation.
Your devices uses private addresses. Private addresses are subnets/networks with the following IP addresses (see RFC 1918):
10.0.0.0 to 10.255.255.255
172....
- 17.7k
3
votes
I am confused about the way a common home router works: Shouldn’t the MAC addresses be enough to forward the information to the correct destination?
On the router, I forward the port 80 (external) to the port 80 (internal) of (instead of the local IP) the MAC address of the PC.
I know this is not how it works, the question is why it wasn't ...
- 249
3
votes
How does a router identify a device with a static ip?
The router generally does not care if a device has a static IP. A device IP looks exactly the same to a router whether Dynamic or Static.
The exception perhaps is the ability for some router to ...
- 48k
3
votes
Accepted
Connect OpenWRT to Eduroam
See the WPA Enterprise (Client) section in the documentation. OpenWRT settings closely map to the underlying wpa_supplicant settings, so first find the correct configuration for that, then translate ...
- 437k
3
votes
Does subnet mask matter for router?
But if i have servers with 10.0.0.47 (/8) subnet masks which gives me enough for host addresses, do i have to assigned my router interface a (/8) subnet mask as well? If i understand correctly the ...
- 437k
3
votes
How routing works on Internet
The $30 home router does a lot less then you may think. Cutting it down to its minimal requirement it needs to
Be able to read the ethernet frame and identify the destination ip of the traffic (and ...
- 69.6k
3
votes
Accepted
How server know where to send response
A router does not transfer IP packets with its own IP address as source. It keeps the original source IP address, so it is not lost.
A corner case is routers with network address translation (NAT). ...
- 623
3
votes
Accepted
Computer connecting to wrong Google wifi router
Your suspicion is wrong. The BSSID is a unique identifier of each wireless base station. Both PCs connect to the same BSSID, and thus are connected to the same base station.
- 16.7k
Only top scored, non community-wiki answers of a minimum length are eligible