Do TCP connections work differently within the same subnet?
- by Dean
I've encountered some network behaviour that confuses me while trying to get Java RMI working.
I use netcat to connect to a local machine:
[my_machine]$ nc -w 1 192.168.0.100 60000 && echo success
success
I try to do the same to my server:
[my_machine]$ nc -w 1 my-servers-ip 60000 && echo success
This doesn't work, unless I explicitly listen on the server socket:
[amazon_ec2]$ nc -l 60000
[my_machine]$ nc -w 1 my-servers-ip 60000 && echo success
success
For the version that fails, the SYN packet receives a RST, ACK in response.
I'm not too knowledgable about this stuff, at this point I only have wild theories such as the one in the question. Any ideas?
Potentially useful details:
Local Machine (192.168.0.100) - Macbook
Remote Machine (Amazon EC2) - Amazon Linux AMI 2012.03
Security Group Settings:
22 (SSH) 0.0.0.0/0
1099 0.0.0.0/0
49152-65535 0.0.0.0/0
"iptables -L" shows no rules set
