I run Centos
[user ~]$ cat /etc/redhat-release CentOS release 6.2 (Final)
How do I check the TCP initial window size in my OS? I need to verify that the IW is 10.
You can do it with tcpdump:
Result is like:
Win and mss values are important to you. Your initial window is WIN/MSS, 10 in first case, 4 in second.