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I'm on a fiber connection with an Ethernet outlet right in the building. My ISP is responsible for the connection up to that outlet. I assume that they use professional equipment. Today my connection went down and a long troubleshooting procedure with a not so forthcoming support ensued.
I tried different devices and different cables without success while they insisted that their equipment is working properly. The two major test subjects were a stationary computer with two Ethernet interfaces and a router, both of them failed to establish internet connection on either NIC. Then I decided to change the MAC address on the connected NIC of my computer and boom, it went online immediately. I did the same thing to my router and also that started working again.
Even if someone knows your MAC address, that knowledge certainly doesn’t help anyone do anything either good or bad.” just as the site used java to find my original mac address, can’t a similar process be applied to trace a person/machine’s location on the internet.
So somehow the ISP's DHCP server had managed to 'ban' all my three MAC addresses, how can that be? What went wrong on their side? Your ISP was having issues the support people didn't know about. It is possible your MAC address was banned for a time if you make too many requests and for some reason your computer/router gives a NACK response to deny the offered config, but I doubt that happened.
The most likely issue was that they had a problem that was fixed while you were fiddling with the MAC address and the support people never even knew about it. If you go back to the regular hardware address it will probably work fine now. Oh I had this problem when i first got Fiber on Verizon FIOS and they just started their 'Business' side.
The limited the number of MAC addresses allowed to go through the fiber with direct connections to it. They expected NAT and only one router like how residential was setup. So my setup was ONT - Firewall Bridged - Network Where in a residential they'd expect ONT - Router doing NAT - Network. In my situation they cut off anything beyond 3 computers because It registered those MAC addresses first.
If you're residential you just need to put your router doing NAT first. Yes I did power cycle the router several times. Only one MAC was visible to the ISP, the router reroutes using NAT yes. I think only two MACS were banned. The router had the mac copied the from the nic from a prior troubleshooting session I forgot about. Okay, if you're using NAT, then MACs have nothing to do with it, since they are only locally significant.
To put that another way, your ISP.can't. see local MACs behind a NAT device. Something else is going on. Edit: actually, let me put a caveat on that.if you are using non-discrete IPv6 addresses, it's.possible.
that your ISP could notice that.but why they would care is beyond me. I think only two MACS were banned.
The router had the mac copied the from the nic from a prior troubleshooting session I forgot about. So basically when you had issues. You plugged in something other than the router to trouble shoot. Found out it 'worked' then tried to plug it back in the router didn't work until you cloned the working address on it.
It's difficult to power cycle an ONT and even doing that won't make much difference. The blocking is done from their side on the router on their end. You need to #1 plug your router in. #2 call your provider to have them do whatever they need to do. By any chance is this Frontier fiber? I was out last time I replied so I was pretty brief. I noticed that the router couldn't get a connection.
It uses some kind of a DHCP protocol to negotiate a WAN address with the ISP's equipment. So I started troubleshooting by attaching a computer system that is normally behind the router and noticed that it didn't work either. That computer has two separate network interfaces and none of them worked. I did it all with the same cable simply because I'm lazy. As I was kind of arguing with the support that insisted that everything is normal. I decided to grab another computer, and saw that everything was working.
I was using another cable too. The support immediately said that something is wrong with my equipment and that is not their responsibility. I replied that that two devices getting faulty at exactly the same time is very unlikely. In addition, I had no problems with file sharing over the local network and the router is connecting properly with the computer that is supposedly 'faulty'. Her response was brief; I don't know how your equipment works!
So while I was with the support and arguing while tinkering with the 'broken' computer connected directly to the outlet, I got the idea to change the MAC address and Bob's your uncle. The router had the same MAC as one of the network interfaces on the 'faulty' computer which I had entered into the router on a prior troubleshooting session a long time ago and then forgotten about it. That's why the MAC 'ban' also affected the computer, I assume. The only strange thing is that both network interfaces on that computer didn't work. So how about this, the current network cable is glitchy? It's a hypothesis I'm stating now.
The cause may be oxidization or a dust particle that has wedged itself between the connectors. So perhaps during a transmission, the cable caused some interference which made the router bomb the ISPs router/switch with NAK's which eventually MAC banned the router. When I tried the cable on the computer's network interface with the other MAC address, the cable still showed faulty characteristics. Then after all the troubleshooting procedures, the cable fixed itself. I wonder if excessive NAKs are logged in routers. I suspect they are not.
I wonder if there is a way to check for such a thing. I have glanced through the logs of the router but nothing of the sorts could be found. So I started troubleshooting by attaching a computer system that is normally behind the router and noticed that it didn't work either. That computer has two separate network interfaces and none of them worked. I did it all with the same cable simply because I'm lazy. As I was kind of arguing with the support that insisted that everything is normal.
I decided to grab another computer, and saw that everything was working. I was using another cable too. The support immediately said that something is wrong with my equipment and that is not their responsibility. I replied that that two devices getting faulty at exactly the same time is very unlikely.
In addition, I had no problems with file sharing over the local network and the router is connecting properly with the computer that is supposedly 'faulty'. Her response was brief; I don't know how your equipment works! So while I was with the support and arguing while tinkering with the 'broken' computer connected directly to the outlet, I got the idea to change the MAC address and Bob's your uncle. The router had the same MAC as one of the network interfaces on the 'faulty' computer which I had entered into the router on a prior troubleshooting session a long time ago and then forgotten about it. That's why the MAC 'ban' also affected the computer, I assume. The only strange thing is that both network interfaces on that computer didn't work.
If their gear is assigning your gear an IP, which it had been doing, there is something wrong on your end. Just because the.switch.
in your router is working, doesn't mean the bridge/NAT functionality is (meaning, file sharing is working while internet isn't). You yourself could have muck'ed something up.
You need to go back to basics. Unplug all of your stuff. Plug the router in to the ethernet connection first. You may have to call the provider so they can reset the ONT. Alternately, if you have access to the ONT, you can unplug the power and disconnect the battery backup, wait a minute, plug it all back in (with the router already powered on). It probably wouldn't hurt to reset your router to factory defaults as I get the sneaking suspicion you've changed some things in there that you shouldn't have. If your router still can't get an IP, something on their end is wrong or your router is smoked, which isn't uncommon with consumer networking gear.
It's a hypothesis I'm stating now. The cause may be oxidization or a dust particle that has wedged itself between the connectors. So perhaps during a transmission, the cable caused some interference which made the router bomb the ISPs router/switch with NAK's which eventually MAC banned the router.
When I tried the cable on the computer's network interface with the other MAC address, the cable still showed faulty characteristics. Then after all the troubleshooting procedures, the cable fixed itself. I wonder if excessive NAKs are logged in routers. I suspect they are not. I wonder if there is a way to check for such a thing. I have glanced through the logs of the router but nothing of the sorts could be found.
Yeah, you're really reaching there. Go back to the basics. I don't get your comment. I changed the MAC address of the router and now everything is working.
The topic being discussed is as the title says; why did changing MAC fix the situation. I still want to figure out why the MAC was banned like this and how to put forth evidence as to how this happened.A lot of times something like this can even be an unrepeatable 'glitch' in the system. Unless you're able to run experiments to replicate a MAC address not working, there's not enough data to even intelligently guess at the cause with any accuracy. I understand the numerous reasons why one want to know the cause of such a problem, but there's simply not enough data at this point. I don't get your comment.
I changed the MAC address of the router and now everything is working. The topic being discussed is as the title says; why did changing MAC fix the situation.
I still want to figure out why the MAC was banned like this and how to put forth evidence as to how this happened. I think it's more of case that the provider bound to a certain MAC. By happenstance, when you changed the MAC, the timing happened to be right where it allowed to reconnect. This was (maybe still is) a problem with Comcast.
If you slapped a new router (or computer) onto their cable modem, it wouldn't connect unless you spoofed the MAC of the new hardware to match the old hardware or power cycled the router. For whatever reason, their hardware locked to that MAC address and the only way to fix it was to power cycle the modem. For whatever reason, their hardware locked to that MAC address and the only way to fix it was to power cycle the modem. This is 100% by design, and how every residential cable modem on their network works. Part of the provisioning config it gets sent on boot tells it how many MAC addresses are allowed on the customer (Ethernet) side. This is set to 1. Have a cable modem?
Go to and the addresses tab. Surfboards will say 'Known CPE MAC Address (Max 1)' and show the MAC it has learned. The only way to clear the MAC table is to reboot the modem. It's not 'for whatever reason' it's working as intended.
MAC is Media Access Control which provides physical connectivity only. IP Address provides Host or Network interface Identification and Location addressing. For your second question, Let we have two connections, one is for Local connection and other is for internet or virtual machines are running in the system. What happen the IP of both connection will be different but the physical address of machine same. In this case what will you do?
In this case IP address defines the address where the system will communicate. The reason for that is the routing. If you have an IP, for example 104.103.84.161 for the www.microsoft.com, every router on the Internet knows, where to send packets to this IP address. They are organized into a tree-like structure in the Internet, where the IP networks of the organizations have a global registry.
In the case of the MAC addresses, there is no such thing. From a MAC address you can only see which company manufactured the chip, but no more. MAC addresses are normally fixed in the NIC firmware, while IP addresses can be freely set everywhere. There is also a deeper reason: in the cases of the NIC, there is no guarantee that you want to make IP traffic on them, it is only a quasi-common standard.
Earlier existed different protocols (for example, IPX, or the microsoft win2000 servers also had one) which didn't use IP, but another protocol over the NIC cards. IP is the standard of the Internet, while the MAC is the standard of the Ethernet. It is not obligatory to use IP from Ethernet, for example in the ancient times there were ARCNET cards which used a quite different protocol (as I know, their 'MAC' were much shorter, too). Or there are VPN protocols which also traffic only IP packets without an Ethernet frame. So, IP is the common of the Internet, and you can connect into it with everything.
Most people connects with Ethernet packets but it is not needed. Btw, having an 'Internet' which uses MAC addresses instead of IP, would be possible, although it would require to develop the complex protocols and shared databases on every protocol layer to use them. They are developed for IP in the times where the Ethernet didn't even existed. So, the final answer to your question is the social inertia.