I'm posting data from my app to my server using NSURLSession when a button is pressed. I can successfully send the data to my server and insert into a database, for the first two occasions, but any time after that, the request times out.
I've tried: changing session configuration (connections per host, timeoutInterval etc), session configuration types, changing the way the data is posted.
Has anyone seen this sort of behaviour before and know how I can fix this issue?
Or is it a server issue? I thought my server was down initially. I couldn't connect to it, nor load certain pages. However, it was only down for me. After rebooting my modem, I could connect back to the server. I didn't have any issues connecting to phpMyAdmin.
If the problem was reproducible after a reboot of the router, then I would look into whether Apple's captive portal test servers were down at the time.
Otherwise, my suspicion is that it is a network problem rather than anything specific to your app.
It is quite possible that the pages you were loading successfully were coming from cache.
Because you said that rebooting your modem fixed the problem, that likely means that your modem stopped responding to either DHCP requests or DNS lookups (either for your domain or for one of the captive portal test domains).
It is also possible that you have a packet loss problem, and that it gets worse the longer your router has been up and running. This could cause some requests to complete and others to fail.
Occasionally, I've seen weird behavior vaguely similar to this when ICMP is getting blocked too aggressively.
I've also seen this when a stateful firewall loses its mind and forgets the state.
This can also be caused by keeping HTTP/HTTPS connections alive past the point at which the server gives up and drops the connection, if your firewall is blocking the packet that tells you that the connection was closed by the remote end.
But without a packet trace, there's no way to be certain. To get one:
If your network code is running on OS X, you can just do this with tcpdump on your network interface.
If you are doing this on iOS, you can do this by connecting your computer via wired Ethernet, enabling network sharing over Wi-Fi, pointing tcpdump at the bridge interface, and pointing your iPhone at that Wi-Fi network.
Either way, that will tell you if there are requests going out that never come back, and more importantly, what type of requests they are, and who is responsible for replying to them. Once you have that information, if the source of the problem isn't obvious, post a link to the packet trace and we'll add more suggestions.
Related
I have a webcam chat room application (so it's many-to-many video sharing) using WebRTC and a mediasoup server.
I am having problems with SOME of my users not being able to get an incoming video feeds to work. It's a difficult problem because I can't reproduce it at all, and I can't easily "remote-debug" the problem since most of my users are very non-technical. So far the only thing I can tell for certain is that it seems to be network-related, not browser-related, as I have had bug reports from people using Firefox, Chrome, Safari, and Edge. I'm running my server (mediasoup v2) on port 443 with no firewall on the server box, so that should make the door as wide as possible. I just don't know what the exact problem is yet so I'm feeling around in the dark.
So, I'm trying solutions. I don't think(?) I have a TURN server set up but from what I have read, it seems like adding one certainly can't hurt, and could help with my situation.
I don't fully understand the entire WebRTC protocol or RFC 7118 (this stuff is really complicated!) or exactly what/where/how a TURN server fits into the bigger picture. It would help, right? A lot of Googling has led to no clear answers. Would love some help! Thank you!
WebRTC tries everything it can do to make a p2p connection, but there are times that it will fail. The turn server acts as a last resort so that the peers can both connect through the turn server. Obviously this is not a p2p connection, so there will be extra latency, and you will have to make sure that your turn server has enough bandwidth to cover all of the connections you expect.
TL;DR, If you need 100% connection rates, you should have a turn server.
I believe AWS has a ready made instance you can spin up, or if you could use this open source coturn server https://github.com/coturn/coturn
On a debugging note... Check your ice candidates type. You should see host and srflx if you only have a STUN server, but if you have a TURN server you will also see relay. You can replicate this issue by discarding the ice candidates that have host and srflx types.
I'm running my server (mediasoup v2) on port 443 with no firewall on the server box, so that should make the door as wide as possible
That is websocket. The media traffic runs over UDP typically and mediasoup uses random ports. A TURN server which is configured on udp port 443 may help in some cases.
The other problem is UDP being blocked which is easy to reproduce with a local firewall.. Mediasoup supports something called ice-tcp which will allow media to run over a TCP connection. You should check if your mediasoup installation uses ice-tcp. If it does not, a TURN server with TURN/TCP will help.
I have developed a WebRTC based application along with Kurento-Media-Server.
Problems with this application is:
It works but only on open network (i.e. if run on a network without firewall).
When in firewall it runs sometimes (once out of 10 attempts).
I have tried several things with the firewall, I have disabled all kind of incoming/outgoing traffic. I have created a port-forwarding for my application as well as Kurento-media server.
I am not sure how much useful this information might be but I am deploying my
application on the same physical box along with Kurento-Media-Server. I have configured google's STUN server on my client.js, I have also configured same STUN servers on kurento using code. I haven't configured TURN server.
Just confirming this, signaling server can be behind firewall along with rest of the application, correct?
I am not sure what to look for now, any help in this area would be great.
EDIT-1
From this link I learned that my current network on which my isn't working it has issues with plain websocket connection, it doesn't allow it, it only allows secure Websocket connections.
EDIT-2
Image of netscan:
In my phone network where my app works fine I see all greens in Websocket's "plain" column.
EDIT-3 Solved
Finally found the problem, We were using a router for testing and development and I found that the router had issues, I used LAN cable on the same router and everything worked fine. Calls from application were working just fine. Firewall related details help in configuring the firewall later on.
Based on your problem description it seems all the UDP traffic is not open in your firewall. WebRTC media run on UDP ports.As you mentioned it works one out of 10 times whch means only few UDP ports are open in your firewall.You are lucky when traffic comes via tose ports.You can open port-range in your firewall and configure the same in kurento-media-server config.Your job should be done.
Even if you configure TURN server you need to open certain ports for outgoing and incoming UDP traffic.For TURN server default port is 3478 or 8443 for sending data towards it but for incoming traffic you need to configure port-range on your TURN server and open those ports in your firewall. Always remember TURN server is assured way to connect but it's always costly.
I normally use MOBAXterm to SSH into my work pc, but when I use my gf's internet connection, it works for only a little while before giving me the above error message.
It also happens when I ssh into other external machines and it also happens when I use putty. I already implemented all the in-build steps MOBAXterm offers that could potentially fix this problem.
My suspicion is that it's related to the internet connection cutting out temporarily, but I don't see why that should be such an issue.
Any advice would be appreciated.
Two possibilities here, the nefarious and the irritating. If you know how to sniff traffic, a pcap dump of the session dying would be extremely useful. Grab it using the stable version of Wireshark.
The nefarious possibility
Traffic shaping. SSH can be used to tunnel VPN traffic. If the ISP is difficult about it (more likely if they're a big ISP) they could happily send RSTs to long-lived sessions.
The irritating possibility
Sketchy home router. If the NAT table is too full, the router's memory is overloaded, or there's a bug in the firmware, the NAT table could drop sessions which would cause what you describe.
Solutions
Try mosh. It uses SSH for session setup, then its own protocol over UDP for the actual session. It's UDP-based so there's no TCP connection to RST, and mosh is designed to survive a nuclear strike. It doesn't even care if your IP address changes mid session.
The problem is likely to be solved using mosh - even if it's the home router, mosh's session continuity will mask the NAT table resetting.
If you want to replace the home router (for example if the same thing is happening to other protocols), and you can get the authentication details for the Internet connection, try swapping it out for another one - preferably a recent high-end SOHO model.
If the connection presents as Ethernet (for example a cable modem, like Virgin) then my standard known-good is the TP-Link Archer C7.
If the connection is DSL-based (copper phone line, or BT fibre), you'll also want a 1-port VDSL (for fibre) or ADSL/ADSL2+ (for copper) modem capable of bridge mode. You'll need this in addition to the Ethernet router.
For VDSL, I'd probably recommend the ZyXEL VMG1312-B. For ADSL/ADSL2+ I'd suggest the ZyXEL P660-R.
I am coding a mac app, which will be a server that serve files to each user's mobile device.
The issues with this of course are getting the actual ip/port of the server host, as it will usually be inside of a home network. If the ip/port changes, its no big as i plan to send that info to a middle-man-server first, and have my mobile app get the info from there.
I have tried upnp with https://code.google.com/p/tcmportmapper/ but even though I know my router supports upnp, the library does not work as intended.
I even tried running a TURN server on my amazon ec2 instance, but i had a very hard time figuring how what message to communicate with it to get the info i need.
I've been since last night experimenting with google's libjingle, but am having a hard time even getting the provided ios example to run.
Any advice on getting this seemingly difficult task accomplished?
The port of your app will not change. The IP change could be handled by posting your servers IP to a web service every hour or whatever time period you want.
Server should run a URL http://your-web-service.com/serverip.php?ip=your-updated-ip and then have your serverip.php handle the rest (put it into a mySQL db or something)
When your client start it should ask your site for the IP and then connect to your server with that.
This is a pretty common way of handling this type of things.
I may be giving entirely the wrong information here, but at the moment we're a bit unsure where to look for the issue. We have a server running on WebLogic, of which version I'm not sure.
Our site has an installer that clients need that can run around 15 MB. Normally, this downloads perfectly fine, but we've recently been finding issues in the download where the browser reports it completed, but the installer can't be opened - it appears that the filesize isn't what it's expected to be either, like the download was just cut off.
The issues are relegated to instances where the user is on a spotty connection, such as a 3G card in their laptop.
It seems to happen mostly on Macs, but it seems like that's because the mac .dmg file is much larger than the windows executable. Still, from my knowledge of network protocols, a spotty network shouldn't cause the specific issue we're seeing.
At the moment, we're debugging several of the layers of the transfer, like our firewalls, but with my meager knowledge of Weblogic, I'm kind of curious if there is something we could be missing in the server's configuration itself.
Unfortunately, I'm not sure if I am able to post the configuration files here - I'm pretty sure at the moment, there are no servlet rules created specifically for the installer's directory - but I was hoping someone here might at least recognize this type of issue and be able to point me in the right direction.
Check if you have any maxpostsize limit set.
Check for the responses that has failed if there's any socket timeout errors seen in the log file.
If you are using a proxy, check for error there related mainly to sockets.
Such issues can come when a tcp socket is timed out at the firewall end, WLS end, Frontend proxy like apache end.
There are few other settings like http connection timeout I think in WLS.
check from admin console-server-protocol-general tab or http tab.