It seems I have this weird issue I can't really understand. I am able to connect to a remote computer (windows machine) with remote desktop perfectly but I am not be able to ping to it. When I ping I get timeout all the time. It is the same ip address and I am using the same computer, so there are no firewall issue I think. From what I know ping is using it own protocol (different than TCP and UDP) so you don't ping to a precific port
Yes it is. The system administrator, and the network administrators (of the several networks you need to use to access the remote machines), are able configure their boxes to disable ICMP. Then ping does not work, but HTTP or ssh (or whatever protocol your remote desktop uses) could work.
ICMP is often disabled for security reasons, and to lower the load on the remote computer. It makes slightly harder to find the remote host.
Related
I created two Qt apps: one client and one server.
I use them to send some data for handle a remote device.
If I am in localhost I haven't issues about them, but when i search to connect them by internet i don't know how to find correct Ip server to connect Socket Client.
How i can find this ip node?
Is there a class to find It?
you cannot find it automatically, if this is what you're asking about.
In real life you would deploy your server on some publicly accessible host, give it a domain name (important part as your host can change the IP address at any time) and connect the client via the DNS domain.
However if you're just playing around and you want to show to the world that your app works, specifying the IP address of the server in your client code would be perfectly fine (assuming you're running both the server and the client in the same network).
In that case, if you're running mac/linux run the command ifconfig (or just ip depending on the distribution). On Windows you can run the command ipconfig. Both windows and linux will give you a similar output resembling this:
Pay attention to the network adapters. There can potentially be many of them. You may have some emulated adapters if you have docker or VMWare, you may have the wireless adapters if you have a WiFi card, and then the ethernet adapters if your computer can connect to the the internet with an ethernet cable. Each of these adapters specifies a different IPv4 address. You want to pick the one that is connected to the same network as your client. So for instance if both your server machine and your client running machine are connected to the same wifi, you pick the address from the Wireless LAN adapter
I have a bit of a bizarre problem. I have a Hyper-V VM and I cannot connect to it via IP address on the host computer.
I intend to use it as an SQL server to host a database for a website while I test it, and the first step I can see in this endeavour is to make sure the IP addresses work externally.
Other PCs on the LAN appear to be able to connect just fine via the IP address on Remote Desktop. I cannot do so. I also cannot connect through SQL Management Studio (named pipes or TCP/IP). Although named pipes gives an error relating to being denied access as opposed to IPs which are just not found.
I have tried pinging both ways:
VM => Host : Always gives a "Destination Host Unreachable" error
Host => VM: Always gives a "Request Timed Out" error
As for netstat -a -n, I can see that the VM is listening to 3389 (default Hyper V port, which makes sense).
Regarding Firewalls, all have been turned off on all machines. I can tell that the firewall is not the issue.
If you need any more information to help me to diagnose and treat the problem, please ask me as I would like to get this sorted as quickly as possible.
Thanks a lot in advance.
Which windows server version do you use?
Windows Server 2016 blocks insecure RDP connections (https://support.microsoft.com/en-us/help/4295591/credssp-encryption-oracle-remediation-error-when-to-rdp-to-azure-vm).
Since RDP uses CredSSP you have to install the current Windows Patches.
Do you can ping the DNS server by IP address from your VM?
Is ICMP (ICMP = the thing you need for ping) on your host enabled?
Here is a Checklist for ICMP:
https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/cc749323(v=ws.10)
Solved,
Just switched to another physical computer and it was fine.
I have an embedded webserver running on a device. Now I want a smartphone app to connect to the webserver. They are on the same wifi network but they don't know each others IP addresses.
I understand that this problem is often solved by implementing the mDNS protocol on the server. But are there any alternatives? Can the server maybe ask for specific IP address or similar?
If it has to be entirely automated, such that the embedded webserver is discoverable, perhaps scan the entire netblock looking for the correct response "http://[IP_address]/yes-im-the-one" from your embedded webserver?
Although beware, some network monitors may then consider the IP of your smartphone/device that does that scan "dangerous" and cut it off from the network - this is probably only a "big enterprise" problem.
...after you "find" your server, perhaps the application should cache/remember this, so it doesn't have to scan next time.
Other things you could do: give your embedded webserver a static IP on the LAN, either by setting this on the device itself, or via a DHCP reservation from whatever is the local DHCP server on the LAN.
What allot of emended devices do is come delivered with a static LAN IP already set on it, then it's up to the sysadmin to change their computer's IP temporarily to be in the same range, then they can visit the webserver or telnet into the default IP, and change it to what they want (to match their network's IP range)
I have got chef-server installed on a centos machine.
Everything is working as expected except that I cannot access the chef-server web interface from another machine on my local network.
I can access the web interface from the centos machine itself:
telnet mychefserver.local 4000
Connected
If I do the same from my machine I have got:
telnet: Unable to connect to remote host: No route to host
I can successfully ping mychefserver.local from my machine
Any idea how to configure nginx with chef-server to access the chef-server from the network?
Since Chef Server 10, the web interface uses normal HTTPS (TCP 443), it only listens on the high ports locally, and nginx proxies as needed to the different backend services. I would try with a normal web browser as telnet isn't exactly great at error messages. Normally I would expect that to mean telnet is getting TCP transmission errors, but maybe it is just confused? If it is really a TCP transmit error then more likely the internal DNS is having issues. .local often means mDNS which has uneven support in some places, I would try an actual IP address to be sure.
My issue was iptables.
I stopped iptables and I can access the chef-server from my local network again.
I have a puzzle I am not able to figure out, I would appreciate any help.
I am connected to a remote desktop using windows default remote desktop utility (Windows 8 locally, Windows 7 remotely).
The remote desktop is not in the same sub-network as my own.
Connection is made through default port 3389. Using Wireshark locally I can confirm the TCP connection being established and the data flow.
Running Wireshark in the remote desktop, I don`t see any flow of data between the two computers.
If I send a ICMP ping from the remote desktop to my computer, it works well and I can see it in Wireshark both remotely as well as locally. But if I send the ICMP ping from my computer to the remote desktop, it fails. I see it leaving my computer through Wireshark, but it never reaches the remote desktop (I don`t see it in Wireshark).
I don't think it is a firewall issue (specially since it can't explain why Wireshark won`t capture the port 3389 RPC flow).
Does anyone have any idea of what might be going on?
I found the main issue.
In Wireshark, turns out it is possible to configure the capture interface with a filter.
To change it, go to: Capture->Interfaces
On the interface being used, stop capturing to enable the Options, there it is possible to configure a capture filter.