My internet stops sending outgoing packets a lot of times during the day, and it lasts 8 to 13 seconds.
Example: in Discord I keep listening others, but they can't hear me. Other softwares have the same behavior.
In my house there are 4 routers, and 1 ISP Modem, all in the same subnet.
All routers have DHCP turned off, and the Modem is responsible por the DHCP.
Modem is 192.168.0.1, and the 4 routers from .2 to .5.
I would like to know if this could be a DHCP configuration problem, or a ISP problem! Any ideas?
I tried connecting my PC to all routers, and even the Modem, and the problem happened in all tries.
You have done your troubleshooting well. By observing the problem without any routers in the mix, you've shown that your trouble is in the modem or, more likely, the ISP network behind it.
One more thing to rule out: completely disconnect your routers from your modem, switch them off, and repeat your test directly connected, with Ethernet not WiFi, to the modem.
If you still have the problem you have proven the problem is with your machine, the modem, or the ISP network.
If the problem goes away in that situation it's possible that some other machine somewhere on your network is occasionally blasting data at the modem.
Four routers sounds like an overly complex setup. The typical modem connects to only one router. Routers actually route packets from an upstream network (your ISP) to a downstream network (your building's LAN). If there's confusion about which router is supposed to do that, frankly it's amazing that anything works. If three of your four are configured as WiFi access points that's OK.
The typical modem doesn't offer DHCP service to its downstream LAN network, because it doesn't know about a network behind it, only one device, your router.
Some ISPs provide combination modem / router boxes. Maybe that's what you have. You may want to review your network configuration.
Try tracert command in the command line to see if your packets are travelling through all these routers. Maybe it will solve the problem or at least displays if the problem is caused in the routing. Or try to see if the problem is caused in a wrong default gateway to the device.
Related
Update:
I know, the WIFI AP is still on & active in this case and the chip should not know about the change, but the question is still open. How should I check the connectivity?
In my project, the internet connection is really important.
After some testing, I have experienced that if I plug out the ethernet cable from my router the ESP32 still thinks, that it is still connected to WIFI, even the
WiFi.status() == WL_CONNECTED
is always true in this case.
So, I have tried out pinging google.com to examine the connection. This works but takes ages to get back the result.
How should I check the connectivity with the lowest resource cost and time?
Even WiFi.status() is unreliable due to the not documented details by Espressif. The API is error prone as the issues on github show.So actually the question is . what do you really want to check? - in my definition internet connection means my line (or aerial) connectionto my ISP is unbroken. This includes
my AP
my router
the ISPs fiber converter in my basement,
the line itself and the
ISPs gateway
This is what I use to determine wether a connection is open. I ping the IP address of the ISP gateway server. So you save time (no DNS resolution, no hops over nodes on the internet. If you mean wether a certain service on a defined server is available, thats slow but then you are 100% sure.
Just a clarification: "ESP32 still thinks, that it is still connected to WIFI" - YES that has to be true because according to the API this ensures client to AP connection and not AP connection to some where else. Normally a good configured router informs its clients about connection loss (in this case the connected AP(s)) and these notify (depending on their config) their clients (or sometimes not or very late)
Technically that result is correct because you are still connected to wifi!
Just because you unplug the ethernet cable doesn't mean your wifi stops. All it means is that your wifi can't get to the internet.
You can try pinging your isp's dns server. It's a lot closer to you than Google is.
Just the ramblings of an old man...
I was reading that in order to capture traffic for more than just my machine I need to put the nic into promiscuous mode. By default the nic seems to filter out the packets which are not meant for it.
My Question is : How come my nic even receive traffic that is not intended for it? Isn't my router supposed to route packets only to the computer for which it is meant?
Sorry - newbie here and this may be an absolute down votable question that I am asking.
I have heard that in case of wireless networks, the traffic takes multiple paths and the NIC combines these signals to form the original signal. So when a NIC sends something to the gateway it will send multiple signals and some if not all may even be captured by your packet sniffer.
Monitor mode also works like this
The short answer: It depends. :)
Wireshark Wiki: Ethernet capture setup should be of help to get you started.
In my college lab, all the PCs are connected via a hub. I want to capture data packets using Wireshark, but it only displays the interface of my own PC. How can I capture the packets of other PCs?
I've tried all the interfaces, and I can't get it to work.
Odds are you're connected to a switch rather than a hub. The problem there is that only packets intended for your network card's hardware (MAC) address and broadcast packets will be sent to your PC. The switch remembers the hardware address of devices plugged into it and performs packet forwarding based on those addresses. This vastly increases the potential bandwidth of your network segment, but makes snooping on other traffic more difficult. You will need to perform what's called ARP cache poisoning. Basically you need to trick every other computer connected to the switch to send its traffic to you rather than its true destination. You will then need to forward those packets not actually for you onto the correct destination otherwise it will take down the entire segment you're on and people will get nosy.
This type of redirection is possible, but it seems like you'll need to do quite a bit more research and understand exactly what is going on before attempting it. To get started, look into the Address Resolution Protocol; understand what a "layer 2" switch is doing; find out how to inject and reroute packets on the network; think about the consequences of getting caught.
If you're serious about moving forward, check out http://www.admin-magazine.com/Articles/Arp-Cache-Poisoning-and-Packet-Sniffing for some starting tips.
Closed. This question is off-topic. It is not currently accepting answers.
Want to improve this question? Update the question so it's on-topic for Stack Overflow.
Closed 10 years ago.
Improve this question
Bit of a random question (and I know a lot of the technology invovled is not described) but are there any networking gurus out there that can answer what is probably a simple M$ networking question that has me baffled?
Connected my laptop to the corporate network today in the same manner I do eveyday. I was allocated an IP address as per normal but unlike normal, I got no connectivity to the internet.
After a reboot and a ipconfig /release /renew the situation was the same. IP address but no connectivity.
So I called in the Techs who replaced my ethernet cable between my machine and the network port and everything sprung into life -- full connectivity restored.
My question: how did it get an IP address using that broken cable?
Most probably, your laptop assigned itself the last IP it was given by DHCP when it failed to get one from the DHCP server.
Which IP did you get? Windows computers get assigned dummy IPs when they do not get one from a DHCP server, starting with 169 if I recall correctly.
There's too many variables to keep a good educated guess. The best guess I can come up with the facts you've given is this:
The cable wasn't broken when it was initially plugged in. Maybe you were able to get an IP address before the cable broke.
As MrValdez already said, there are really to many unknowns to make a good guess. But one thing to keep in mind is, that just because one event follows another it is not necessarily caused by that event. This is also known as "Correlation does not imply causation".
It might well be, that the time to replace the cable was long enough that the real problem (router, ISP or some other thing along the path) could be solved by someone else (without knowing about your problem) or just vanished on its own.
If the cable was broken, you would get an error network "Not Connected" in the icon in the system tray. If you network connection was up, means the cable was OK.
If the cable was not of the right type, then you could have had connection up, but Ethernet negotiated to 10Mpbs/Half Duplex, which can cause a lot of pain to the use who's not aware of it, including symptoms like no connectivity, dropped packets and hence slow connection, etc.
After that, if you got an IP address beginning 169.184.X.X, that would mean that DHCP failed for whatever reason, and your laptop assigned itself a default configured IP address.
If the IP address you got was what you normally get in your LAN environment (the once with which you usually connect to the internet), then there might be some firewall issues, or something else wrong with your corporate network's router, which the Tech guys might not be too willing to share with you :-)
It's impossible to be sure but here are a few:
Network card driver: I've experienced very random things with HP laptops and ethernet cards. Usually a reboot fixes that. Green connectivity light doesn't always mean 'go', sometimes the drivers are responsible for turning the light on.
Loss of connectivity in the cable or the network plug in the compute.
Duplex negotiation problems between the switch and the computer
Maybe trying gigabit ethernet on a 4 wire cable?
If it was me I'd try an ethernet sniffer (like tcpdump or wireshark) if this happens again, see if you're getting anything in. Ping results would also be nice (to IP addresses, not hosts).
The cable and/or connectors were flaky. DHCP is done using very small UDP packets, and if enough of them are sent, eventually they'll get through. The DHCP retry mechanism is very robust, so I wouldn't be surprised if you lost 95% of the packets, and it was still enough to get an IP.
However, once you start sending larger packets for TCP/IP transactions you'll find that the 95% loss drops enough packets that even with durable TCP/IP, it's too tough to get anything useful through.
There is a lot of history here, so please bear with me.
Our home network used to be fine when we were with Comcast, but we wanted better speed and reliability, so we switched to FIOS. At that point, the Wifi connections from my Raspberry Pis stopped working. I got frustrated after a couple of weeks of trying to discover the cause of the problem and eventually put it aside.
The other day, I started to configure a new Raspberry Pi 4 that I plan to use on my new Sphero RVR. I set it up following the usual directions and the Pi connects to the Internet without problem over WiFi, but I can't ping it from my Windows 10 desktop.
So I started digging. I downloaded the Fing app onto my Pixel 3 Android phone and looked at the network. I immediately noticed that all the devices now have a 10.29.179.xxx addresses. That easily explains why I can't ping from my PC to the Raspberry Pi. They aren't in the same address space.
I did discover that I can ping the Raspberry Pi if I use the IPV6 address. I can even get PuTTY to connect using the IPv6 address, although I was unable to successfully login. I don't know what is causing the login problem, but it's probably something mundane.
I suspect that I can make my Rpi conform to the rest of the network using a static IP address, but that might cause problems if I take the robot somewhere else to demonstrate what it can do. What I would like to understand is why most of my network, using DHCP, is on the 10.x.x.x network and the Raspberry Pis seem to wind up with 192.168.1.xxx addresses.
One further wrinkle. We have two routers, the FIOS router, and a LinkSys WRT1900AC, which is the router on which WiFi is enabled.
I suspect this problem is caused by having the two routers or by something inherent in the way the Raspberry Pi interacts with DHCP.
I would like for my Raspberry Pi to configure with an IPv4 address I can use, no matter what network I am connecting it to, and I'd like to understand why this problem is happening in the first place.
Let me know what additional information you'd like to see.
* Additional Notes *
As to the comment that I have not done research. I spent a week reading through stackoverflow problems and reading up on documentation of DHCP without finding the answers to my question. I do not ask questions idley. I ask questions when I cannot find answers and need the help of people more expert than myself in the areas in which I am having trouble.
I have solved the login problem. It was a stupid password mistake.
So now I can login, over wifi, using the IPv6 address, but not with the IPv4 address.
On the FIOS router, both the 2.4 and 5GHz wifi channels are turned off.
As suggested by Ljm Dullaart, the problem was that there were two DHCP servers on the network. After I turned off the FIOS DHCP, my problems went away.