I have a sample Chrome packaged app which uses the Chrome sockets API to perform DNS service discovery. The heavy lifting is borrowed from the example here:
https://github.com/GoogleChrome/chrome-app-samples/tree/master/mdns-browser
I just use service names such as _pdl-datastream._tcp.local (instead of the default of _services._dns-sd._udp.local).
On both my Ubuntu and Windows setups (Chrome 25.0.1364.172), the app can successfully find my network printer; I can list its IP address and service instance name. However, it fails in Chrome OS on my Samsung Chromebook (Chrome 25.0.1364.173); nothing is found.
Any idea what the problem might be? Is this a known issue?
You should check if it's the default firewall. On a Chromebook by default I believe all incoming connections are blocked. If you're running in dev mode you can do the following to allow all incoming udp traffic to test whether this is the problem:
Press Ctrl+Alt+T to bring up a terminal window and type the following
shell
sudo iptables -I INPUT -p udp -j ACCEPT
Yes, Chromebooks default to a restrictive firewall. However, if the incoming packet matches an outgoing one, the incoming packet should be permitted. Here's the list of firewall rules.
According to the bug report created by Haw-Bin, this is verified as fixed since end of 2013.
Related
I want to connect to a locked (cannot be modified and I do not have permissions to log into) windows vm which is hosted in a linux machine. Until now these two machines were communicating via port 2277. However for security reasons, the port 2277 is only accessible via localhost (127.0.0.1).
The original proposed solution was to use ssh-tunneling. However since the hosted windows vm will always stay with the linux machine, so I was thinking something simpler.
This Windows virtual machine has ip 192.168.0.1 and the default gateway is 192.168.0.2. The later is the ip address that my linux machine can see.
After searching the internet I tried
socat TCP4:192.168.0.1:2277,reuseaddr,fork TCP4:127.0.0.1:2277
as well as some other random combinations without success.
My understanding is that this failed because for socat to work both sockets must be open.
However the first one is not open by default (checked with ss -ltn) as I need to run the windows service first (which it cannot run as it cannot communicate with iphost:2277)
Any ideas on how to proceed?
Socat provides the retry=N and forever options to handle situations like this. Thus, try something like this:
socat -d -d TCP4:192.168.0.1:2277,reuseaddr,fork,forever TCP4:127.0.0.1:2277
With the interval=<seconds> option you can specify how long Socat waits after each failed attempt.
It turns out that the command that I wanted was the following
socat tcp-listen:2277,bind=192.168.0.1,fork,reuseaddr tcp:127.0.0.1:2277
The retry=N and forever options could be also useful.
I was using WSL to run ROS commands, and at a point i had to enable system to respond to broadcast icmp requests (for a multi master kind of a setup) i.e. on linux i had to make sure
cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
returns 0. but WSL does not contain such a file, so i was thinking of enabling it on windows. All the sources i have gone through suggest me to add a rule to firewall but my system is not responding to broadcast ping even when my system's firewall is turned off(domain, private and public have been turned off same with my buddy who is no the same network). i am using an android phone's mobile hotspot to check this.
it would be great if someone could help me on this.
thanks in advance.
I asked something similar
I don't know how to do it purely on WSL. But on windows you have to start the "TCPSVCS.EXE" process. located on System32
I have installed the multipath TCP connection and have 2 interfaces active in my pc. H want to see the mptcp connection working on my device. How do I check that subflows are actually created ?
I tried to connect with multipath-tcp.org and used iperf to check if infact subflows were created but I could see only a single entry in its result. I have seen the related questions, but they don't answer my question i.e. how exactly could i see the subflows in action.
You must connect to a mptcp enabled server to have subflows created otherwise mptcp just falls back to normal tcp. Also, you have to configure the kernel at runtime (you can select fullmesh option) as mentioned in the official website. And, obviolusly, you must have at least 2 interfaces active.
Then tools like iptraf, ifstat can be used to monitor bandwidth in/out.
I found this to be helpful.
1) Open two CLI at Linux environment;
2) Set Wireshark on for capture your packets:
Use option to filter TCP connections, that's make it easy to understand the TCP behavior.
3) Use first CLI to porform iperf as server (iperf -s) and the second to perform as client (iperf -c 127.0.0.1)
After all, you can check the subflows in the Wireshark. Further, you can explore it deeper :)
I have installed andlinux Beta 2 on my WinXP. Everything works fine until last night, I don't recall that I ever changed anything on network configuration or andlinux setup, the network stop working inside andlinux. With that said, I mean open a KDE console, I do "ping yahoo.com", I see DNS is resolved correctly, however, no response at all.
My andlinux is startup as a WinXP service. Open windows task manager I can see following services are up and running:colinux-daemon.exe colinux-net-daemon.exe colinux-slirp-net-daemon.exe
On andlinux side, there are two network interface eth0 and eth1. eth1 is configured to communicate with local WinXP. I configured it to use samba to access windows directories, no problem. From WinXP side, I can use ssh to login into andlinux box via eth1 IP address.
eth0 is configured as slirp, no port forwarding. eth0 has IP=10.0.2.15, default gateway is 10.0.2.2, netmask=255.255.255.0; These are configured in /etc/network/interfaces. DNS is 10.0.2.3, which as I just mentioned resolve yahoo.com correctly.
On the windows side, internet works fine. I disabled firewall on all network interface. I rebooted my laptop, no luck. I searched over inet, seem no one has this problem. People say network is done if they kill the colinux-slirp-net-daemon. What frustrated me is that this whole thing worked well, but for no reason it's broken all the sudden. Anyone has experience on this issue, please help, appreciate!
I thought I had the same problem, but then found my andLinux system's network connectivity was actually working fine, and that several things made it difficult to tell what was going on.
Test I did to validate connectivity: wget www.yahoo.com
Behavior I observed that made troubleshooting difficult:
Pings from andLinux - not all hosts will respond to pings from the andLinux OS (ie Ubuntu, not the Host Windows OS). According to my packet captures the pings appear as UDP pings instead of ICMP pings once they leave the host OS's adapter. The major IPs/hosts (like yahoo, google, 4.2.2.2 etc.) on the internet I usually ping to test connectivity currently don't respond to these type of pings.
Traceroutes from andLinux - even when successful, these never show more than 2 hops when done from the andLinux OS. If successful, both hops show 10.0.2.2. If unsuccessful, the second hop just times out. Not sure why, I'm sure there is an explanation.
Packet captures - at the host OS level, the capture (eg wireshark) must be done on the physical interface the traffic is going over. I was initially capturing on the TAP-Win32 Adapter but this only showed X Window traffic.
Installed apt sources URLs no longer valid - Ubuntu 9.04 is long out of support by now, so the URLs in the apt sources.list file didn't exist anymore. This is what got me thrown off in the first place, because I didn't troubleshoot this specifically and just tried to test my internet connectivity first, then got confused by the ping and traceroute behavior seen above. Changed http://us.archive.ubuntu.com/ubuntu to http://old-releases.ubuntu.com/ubuntu/ in sources.list and was good to go.
I am new to Linux and I have my application running on windows for a while and for file Transfer stuff we use third party sftp and it has been running well both on Active and Passive mode.
Now i am migrating my app to support Linux OS, and i'm facing problem in FTP Active mode, where i can transfer files in Passive mode.
I tried through FTP command where i can transfer files in both mode and when it comes implementations it gives me the following error:
500 Invalid PORT Command.
and the before this error the ftp command looks like :
PORT 0,0,0,0,234,96
where for passive it works fine.
Do it need to enable any firewall settings in linux, Please help me out.
PORT 0,0,0,0,234,96
The first four octets represent the IP address, which in this case, seems like is absent. So you either missed out declaring the client's IP address in the application or may be there is some other issue with the IP addresses. Try this link for more info: FTP
Also check if its getting connected when you turn off the Linux firewall.
/etc/init.d/iptables stop