I have a requirement to transfer/multicast a large file about >40g of file from a server to multiple clients at the same time and this will be done for only once. Is there any good protocol to do that in Linux? I tried using UFTP, but it didn't work.
UFTP should be a good tool for this situation. If the server and clients are on the same LAN, there shouldn't be any issue with them communicating. If there are one or more routers separating them, then you would either have to configure routers to allow multicast traffic to pass or you could use UFTP's proxy servers to create a bridge between different network segments.
You could use the excellent bittorrent protocol and make it private by using Bittorent Sync.
Go to Bittorrent Sync Web Site for details.
The main advantages I see are :
It's design to transport large files (if you have a network disruption it's not a problem)
It's free
It's cross plateform : Windows, Linux (i386, x64, ARM, PowerPC), FreeBSD, Mac, Android, IOS, and more ...
It's secure (you provide the encryption keys)
It's quite simple to configure
Related
i have a problem with local network connection. i'm writing an iphone application and i need to read/write files to a computer. Both devices connected on the same network.
if it's possible, i want to get connected computers ip list, select one of them and read/write files like pdf, doc, txt etc.. if it's not possible to do, i will write the computer ip which i want to connect. There is no problem, both of solution is OK.
But i dont know what do i do after get the computer's ip ?
i found this chat client/server on local, but i got it very complicated.
Anyone have any idea about this ?
You'll need to have a server running on the computer, which can show files and allow for files to be read and created.
Easiest is to run a webdav service on the computer, Apache provides the mod_dav module for this purpose.
The iPhone app then becomes the client. I'd suggest using neon for this purpose. It's a C library that provides listing, reading and writing files on a remote webdav server.
That's how I would do it.
1) Find the network address of the computer you want to connect to. For this you can make use of Bonjour. It's very easy to setup because Bonjour handles the resolving of address for you.
You just have to publish a service (e.g. _myprotocol._tcp) via the ´NSNetService` class which is available on iOS and OS X (Windows too)- in your case you would publish the service on your computer.
Then you search for the service with the NSNetServiceBrowser class.
When you found a service you can then resolve it. This actually gives you the network name of the other device.
2) Connect to the other device via a tcp socket. The CocoaAsyncSocket library is very good at this. This project also includes some examples. One example already provides a bonjour server and client implementation.
i found exactly what i want. The solution is here
We have acquired a 4 channel GSM Gateway, model GoIPx4-G610 (the manual is titled "GoIP Series SIM Card for GSM Voice Gateway - GSM VOIP Gateway").
We are looking to develop a custom application to control the GOIP gateway. We have developed in the past custom applications that controlled simple GSM modems through AT commands for sending/receiving SMS messages in particular.
Although the gateway can be controlled through SIP we would like to control the GSM modems embedded in the gateway through AT commands if possible. This is because of the fine grained control AT commands offer and because we do not need VoIP features since we need only to send/receive SMS messages.
The gateway runs an unknown Linux instance to which we can connect through telnet. Unfortunately we do not have the credentials to authenticate to it. The gateway also has a web http administration interface to which we can authenticate but we can't find there settings/information related to channels that we can use for AT commands.
The documentation is very poor and the provider could not offer us any helpful information regarding this.
If anyone knows how we can send AT commands to the modems inside the gateway it is highly appreciated.
Up to now we have tried a brute force attack on the telnet interface to find the credentials with no success. We hope that once we can connect to the Linux instance driving the gateway we can connect from there to the modems through serial connections (to send AT commands) and we can reconfigure it to redirect the connections outside of the modem or to make an interface for sending commands to the modems.
The device has an update firmware option (through the web interface) which always gives the error "download failed". Downloaded the firmware (.pkg file) manually from their update pages and extracted the files from the embedded Linux distribution that should correspond to the ones placed on the gateway. The files were kept in the pkg file as an ROMFS compressed image which we mounted on a test station to see the files (probably the running OS on the gateway is an uClinux distribution).
Did this hoping that we can find there the /etc/passwd file which could be cracked with classic attack. However didn't found it and probably that file is placed on the gateway flash memory (contrary to the Linux files which are stored on the ROM memory). So if there is a way to erase / reset this flash memory that could be a solution (in case the gateway doesn't refuse to boot without those files). Another solution would be to be able to access the flash memory with the passwd file if there is such thing.
You might take the lid off and see what parts are inside.
If it's a general purpose processor with a published data sheet and without a lot of code security features, you might be in luck. For example, you might find:
By guessing headers or tracing from known pins, a console serial port, either logic level or RS232, hopefully with a shell listening
A boot mode pin for the micro connected to a resistor, which you could jumper to cause the micro to boot to a uart bootloader where you could download a new system image, or patch the existing one. If you are lucky the bootloader would be something known, like u-boot.
A JTAG port for the processor
A removable storage device which you could remove and alter
an SPI flash which you could carefully tap into and alter
A flash chip which you could desolder and transplant to a programmer
You could also make a GPL sources request for the kernel and whatever else from the vendor. Or even just trying to identify versions of things like a web server could help you look up any known exploits. Since it seems you have a similar system image to that which is installed, looking through it could be helpful - look for additional daemons running, listening on ports you weren't previously aware of, left over debug support, etc.
I am the developer of the GoIP you've purchased. Instead of trying to hack the GoIP, did you contact us to support your development of custom applications? Here are the updates of GoIP for you.
GoIP now supports SMPP. This could be an alternative to using AT commands to send and receive SMS.
API (Application Programming Interface) for GoIP is now available to support your custom application development.
If AT commands are still the preferred method, please contact us and I would be happy to discuss with you further.
Setup:
I have client C connecting to server S
Both C and S are on the same machine
In C the server address is hardcoded to 127.0.0.1. Likewise, in S the client address is hardcoded to 127.0.0.1
Problem:
I want to be able to sniff the traffic between the client and the server.
Due to the configuration, I cannot move the client nor the server to different locations (the address are hardcoded)
Installing the loopback interface and using tools like Wireshark+WinPcap doesn't lead anywhere (was actually already known but was worth a try)
RawCap, suggested in another topic, doesn't work. IP 127.0.0.1 is listed, but does not record any traffic.
Using rinetd to route the traffic elsewhere, as suggested here doesn't work (cannot bind on 127.0.0.1)
Not interested in using a HTTP local proxy, such as Fiddler, because I'd like to capture also other protocols
Two commercial tools work, specifically CommView and Local Network Monitor, which means it must be possible to do that ;)
How can I do to capture the traffic?
Any pointer on functions I should use or documentation I should read?
Thanks!
Basically you need to write a TDI filter driver to achieve that... for some pointers see:
http://msdn.microsoft.com/en-us/library/windows/hardware/ff565685%28v=vs.85%29.aspx
http://msdn.microsoft.com/en-us/library/windows/hardware/ff563317%28v=VS.85%29.aspx
Another option is to write a WinSock LSP.
BEWARE
Since Windows 8 it is strongly encouraged to use WFP (Windows Filtering Platform) for this sort of thing...
Although it might be more cost-effective to just use/buy an existing solution - esp. if you are not a very experienced driver developer...
Use RawCap, which can solve your concerns, see this
I'm quite new to freeBSD switching from Linux.
I read about jail, the solution sound great for Server Systems.
So my idea for my webserver was to create 3 jails.
One jail for mysql, one for nginx and one for php-fpm.
Now the jails have to communicate with each other. How do I do that?
Over IP? It would be a big overhead but secure.
Here is an example:
CLIENT
-> TCP/IP -> NGINX
-> TCP/IP -> PHP-FPM
-> TCP/IP -> MYSQL
-> TCP/IP -> PHP-FPM
-> TCP/IP -> NGINX
-> TCP/IP -> CLIENT
With Sockets: That would be a security los..
create a directories on the host system
create a directories in the jails
merge the directories
Which solution do you use?Or do you have better solutions?
I would not separate php-fpm but it's possible. The overhead for IP communication is not that big these days and not that important considering the processing that the database and php processor need to make is far bigger. Especially since there is no actual wire involved. The packets are routed through the interface via a loopback construct and don't hit the wire.
The advantage of separation is that you can move the jail to another physical machine if need be and moving jails is a breeze.
To clarify why not to move php-fpm in a separate jail is that modifying the website becomes a two-task process for static content (images) and dynamic content (php files). The advantage is that a breach in the webserver software is not able to modify php code. This is also why you should not nullfs your php code onto the webserver jail if you plan to separate as it would defeat it's advantage.
I really don't know if it's the best solution, but if you can use Unix domain sockets you can share a mount between the three jails. The namespace is isolated (they can't create a socket outside the shared mount point) and they should be able to communicate.
To create the shared mount, you can use a nullfs mount. A nice (rather advanced) guide about jails also speaks about nullfs mounts. Of course, this mount point should be used only for the sockets, the other files should stay separate.
Again, I don't know if those applications can communicate over Unix sockets, but if they can you're probably set.
I am testing a thick client which is connected to a database, need to sniff traffic b/w tcp port on same machine
WireShark (formerly Ethereal) will work perfectly, if you're not familiar with it, it can be a little tricky on OSX, Windows it's no problem and Linux can be a headache. You can download it here http://www.wireshark.org/, and read a short-primer here - http://www.ipprimer.com/packets.cfm
Essentially there's a capture phase, and then you can work with the data – for your purposes you can live-capture and filter the output to the packets on the port/destination you care about, I've used it many-a-time to debug dodgy home networking, or problems at the office.
Beware if using MySQL and localhost for example, this is a key-word for MySQL and it will infact use the socket instead.. which makes things a matter more complicated, you can circumvent this problem by always making sure to use 127.0.0.1 if working with MySQL. (Perhaps other software uses this convention?)
You can try some tools like WireShark.
Assuming you're on Windows:
I'd split the client and server across two machines, either two real ones, or a VM with something VMWare. Then I'd use Wireshark.