The Ping command will test the quality and latency of your connection. If it shows four "round-trip" reports with a clean reply (does not give any messages like "not found," "timed out" etc.) your connection is healthy.
Before you use the ping command, you will want to know which host to ping. Use the List of Networks below to find the host closest to you. Alternatively, if you are logged into TWS, click the green DATA text in the top right corner of the TWS menu bar. You will see the host to which you are connected in the Market Data Connections list tagged as "Primary."
To ping a network, open your command prompt by typing "cmd" in the Search box (for Windows). At the prompt, type "ping Primary." For example, if your Primary server is ndc1.ibllc.com, type "ping ndc1.ibllc.com" A healthy ping and response should look as follows:
Pinging ndc1.ibllc.com [64.190.197.40] with 32 bytes of data:
Reply from 64.190.197.40: bytes=32 time<10ms TTL=254
Reply from 64.190.197.40: bytes=32 time<10ms TTL=254
Reply from 64.190.197.40: bytes=32 time<10ms TTL=254
Reply from 64.190.197.40: bytes=32 time<10ms TTL=254
If the ping results show excessive latency (>500ms), timeouts/packet loss, or no replies, a network problem exists between you and the IBKR network.
List of Networks
ndc1.ibllc.com - New Jersey
cdc1.ibllc.com - Chicago
zdc1.ibllc.com - Zurich
hdc1.ibllc.com - Hong Kong
mcgw1.ibllc.com.cn - Mainland China