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I am successfully connected to a VPN network, I can RDP to remote PC and ping the servers (remote PC and servers in VPN's network). However, I cannot http/sftp the server's sites through home's modem/router (the site takes a lot of time to load and then return Network Error or Timeout error). When I connect to VPN with mobile hotspot, I can http/sftp to the site without any problem.

I checked the home's network subnet and the VPN's network subnet and both are different:

Home network subnet: is 192.168.0.X
VPN network subnet: is 192.168.1.X
Subnet mask is: 255.255.255.0

Additionally, I disabled the firewall in my router with no help. What else I can do.

Case:

Assume I have a site hosted in server with IP: 192.168.1.50. From my local network, I can ping the server after connecting to VPN but I cannot browse the site using http://192.168.1.50 or sftp to 192.168.1.50.

Update

Here is the result after running tracert -c 192.168.1.50:

Tracing route to 192.168.1.50 over a maximum of 30 hops

  1    18 ms    12 ms    19 ms  10.8.0.1
  2    13 ms    20 ms    12 ms  192.168.1.50

Trace complete.

server route info:

0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eno1
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.25.0.0      0.0.0.0         255.255.0.0     U     0      0        0 br-8730262616cd
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eno1

Wireshark:

I installed and ran wireshark in my local PC and tried to call server with IP 192.168.1.150. After connecting to VPN, I was assigned IP 10.8.0.10. The handshake and TLS was successful but wireshark gave a warning on the last TCP exchange:

enter image description here

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2
  • Run a Wireshark capture on the server while you attempt a HTTP/SFTP connection to it from your machine. This will at least tell you whether or not your requests/connections from your machine are making it to the server, and if it's just an issue with the server connecting back to your machine. Running Wireshark on your own machine may also reveal some clues.
    – Luke Humberdross
    Nov 16, 2020 at 12:33
  • @LukeHumberdross I ran wireshark on my PC and httped the server, I noticed wireshark saying warning on the last TCP exchange between my pc and the server. Please check my updated question with wireshark for the last TCP exchange.
    – Coderji
    Nov 18, 2020 at 8:26

2 Answers 2

Reset to default
2
+50

It might be a MTU issue. Try to set your VPN Tunnel NIC MTU to e.g. 1420. This kind of issue happen if you're using Packetencapsulation e.g. in IPSec

https://www.cisco.com/c/en/us/td/docs/interfaces_modules/services_modules/vspa/configuration/guide/ivmsw_book/ivmvpnb.pdf

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  • Thank you for your answer, but this didn't work, I tried to change the MTU in the VPN but no luck, I also tried to change the MTU on my router and it didn't work as well
    – Coderji
    Nov 18, 2020 at 7:57
  • When you say 'MTU in the VPN' have you changed the MTU on your local PC ?
    – schmichri
    Nov 18, 2020 at 10:45
  • 1
    You are right, it worked! the MTU was the problem, I calculated the optimal MTU I needed and changed the MTU on the router and my PC and now I can naviagate with no problem!
    – Coderji
    Nov 18, 2020 at 11:12
1

It is unclear if you are pinging from remote PC you RDP'd to, or from your home-PC. -I am assuming you pinged from remote PC. You have a connection to the remote PC so either the remote PC has a route entry that points back to your home network, or the servers have route entries that points to a different 192.168.0.X network than yours. -When you try to connect to them, you are probably reaching them, but the servers do not know how to connect back to your PC.

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5
  • No I pinged from my local PC not remote, assume that I have a site in VPN's server with IP address 192.168.1.50. I can ping the server my home's network after connecting to VPN. But I cannot browse 192.168.1.50 from home's network.
    – Coderji
    Nov 16, 2020 at 12:13
  • What happens if you do a tracert -d (Windows) or traceroute -n (Linux/Mac/BSD) from your home-PC to 192.168.1.50? -Do you have access to the remote server, can you do a netstat -an on it? -I still believe it is a routing issue from the server back to your home network and to sort it you would need to change the route-table on the server. That you can ping 192.168.1.50 means you can reach it, it does not necessarily mean it can reach you.
    – Sturban
    Nov 16, 2020 at 13:03
  • I have updated my answer with trace log of tracert -d. I can run netstat -an but not sure what to do, it listed a long list. Can you please ellaborate more on what I can do with it?
    – Coderji
    Nov 18, 2020 at 8:02
  • Apologies, I meant netstat -rn or alternatively route print or if the server is not on Windows: route -n. -It will print out the route-table on the server.
    – Sturban
    Nov 18, 2020 at 10:07
  • Thanks for getting back to me, the server is linux based so I ran route -n. I have updated the question with the info needed. Honestly, I don't know how to interpret it.
    – Coderji
    Nov 18, 2020 at 10:44

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