Revision history [back]

I am irritated about the following scenario:

I am running a MVC application on an IIS 10 Webserver. While calling the URI, it takes about 10 seconds until the application starts to get called (IDLE time). Having no real explanation for the occuring idle, I started to dig deeper using wireshark and stumble across the following phenomenon: The Initial TCP Handshake is incomplete (Missing ACK) 1. Client -> Server (SYN) 2. Server -> Client (SYN, ACK) 3. Client -> Server (ACK never reaches the server)

Note: The topology is as described below. Client -> Gateway -> Router -> Server

I used wireshark on client-side as well as on server side. The server resends the SYN,ACK tuple two times, after about 10s IDLE time, the connection is established nonetheless. Looking at the appropriate RFC, this behavior is normal (the ACK is sent by client indirectly while sending the data). The ACK never reaches the router, so where could it get possibly lost? And why does it get lost EACH time? Could it be some router (Mikrotik) setting, like No-ACK? Is the missing ACK the reason for the 10s IDLE delay?

I am irritated about the following scenario:

I am running a MVC application on an IIS 10 Webserver. While calling the URI, it takes about 10 seconds until the application starts to get called (IDLE time). Having no real explanation for the occuring idle, I started to dig deeper using wireshark and stumble across the following phenomenon: The Initial TCP Handshake is incomplete (Missing ACK) 1. Client -> Server (SYN) 2. Server -> Client (SYN, ACK) 3. Client -> Server (ACK never reaches the server)

Note: The topology is as described below. below.

• Client -> Gateway -> Router -> ServerServer1 -> Server2

Note: The Client is redirected to Server2 by Server1. Thus the page load time sums up to ~20seconds. The first 10s are reached by hitting Server1, and the next 10s by being redirected to Server2.

I used wireshark on client-side as well as on server side. The server resends the SYN,ACK tuple two times, after about 10s IDLE time, the connection is established nonetheless. Looking at the appropriate RFC, this behavior is normal (the ACK is sent by client indirectly while sending the data). The ACK never reaches the router, so where could it get possibly lost? And why does it get lost EACH time? Could it be some router (Mikrotik) setting, like No-ACK? Is the missing ACK the reason for the 10s IDLE delay?