Why are applications not seeing SYN/ACK on the Windows guest?
Posted: 17. May 2022, 21:07
I have a Windows guest, and when I try to access a website on the same subnet (using curl, telnet, or a browser), I get a timeout. Here's the interesting part: when I run Wireshark on the Windows guest, I find that a SYN/ACK is actually coming back from the server that I'm trying to reach, but my Windows guest never sends an ACK in response. It re-transmits its SYN as if no SYN/ACK were received:
The guest has a single network adapter; it's a Bridged Adapter with Promiscuous Mode set to Allow All. If I curl my target server with the wrong destination port (curl 172.19.0.3:8887), I immediately get a 'Connection refused'. (And when I try to access a website outside of the subnet, I get 'curl: (7) Failed to connect to 74.6.143.26 port 80: Network unreachable'.) I'm rather out of my depth here.
I have Windows Defender Firewall turned off.
Having a look at my ip config with netsh shows:
I am running VirtualBox 6.1.32_Ubuntur149290. My guest is Microsoft Windows 10 Enterprise Evaluation 10.0.17763 N/A Build 17763. My host is Ubuntu 20.04.
The guest has a single network adapter; it's a Bridged Adapter with Promiscuous Mode set to Allow All. If I curl my target server with the wrong destination port (curl 172.19.0.3:8887), I immediately get a 'Connection refused'. (And when I try to access a website outside of the subnet, I get 'curl: (7) Failed to connect to 74.6.143.26 port 80: Network unreachable'.) I'm rather out of my depth here.
I have Windows Defender Firewall turned off.
Having a look at my ip config with netsh shows:
Code: Select all
Configuration for interface "Ethernet"
DHCP enabled: Yes
IP Address: 172.19.235.111
Subnet Prefix: 172.19.0.0/16 (mask 255.255.0.0)
InterfaceMetric: 25
Statically Configured DNS Servers: 8.8.8.8
Register with which suffix: Primary only
WINS servers configured through DHCP: None
Configuration for interface "Loopback Pseudo-Interface 1"
DHCP enabled: No
IP Address: 127.0.0.1
Subnet Prefix: 127.0.0.0/8 (mask 255.0.0.0)
InterfaceMetric: 75
Statically Configured DNS Servers: None
Register with which suffix: Primary only
Statically Configured WINS Servers: None