0

I saw many posts about the subject, but none of the suggested solutions seem to address my problem.

I am using simple echo client-server programs test connectivity to Amazon EC2 instance running Ubuntu 12 64 bit. (Java EchoServer ; Java EchoClient )

Here are the facts:

  1. I created a rule in the security group enabling Inbound TCP on port 22000
    TCP Port (Service) 22000-22001 Source 0.0.0.0/0

  2. Ubuntu firewall is disabled
    sudo ufw disable

  3. When I try EchoClient [amazon-instance-dns-addr] 22000 from another Amazon EC2 instance it works fine as expected
  4. When I ping [amazon-instance-dns-addr] from external machine I get responses (I enabled the ICMP rule in the security group, too).
  5. When I try EchoClient [amazon-instance-dns-addr] 22000 from external machine it fails to connect.
  6. In wireshark running on the external machine I see that the remote side replies with RST to my port 22000 SYN.

So bullet #5 is the problem. I do not see what I am missing. I would appreciate some help here.

Update: iptables -L output.

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ufw-before-logging-input  all  --  anywhere             anywhere            
ufw-before-input  all  --  anywhere             anywhere            
ufw-after-input  all  --  anywhere             anywhere            
ufw-after-logging-input  all  --  anywhere             anywhere            
ufw-reject-input  all  --  anywhere             anywhere            
ufw-track-input  all  --  anywhere             anywhere            

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
ufw-before-logging-forward  all  --  anywhere             anywhere            
ufw-before-forward  all  --  anywhere             anywhere            
ufw-after-forward  all  --  anywhere             anywhere            
ufw-after-logging-forward  all  --  anywhere             anywhere            
ufw-reject-forward  all  --  anywhere             anywhere            

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
ufw-before-logging-output  all  --  anywhere             anywhere            
ufw-before-output  all  --  anywhere             anywhere            
ufw-after-output  all  --  anywhere             anywhere            
ufw-after-logging-output  all  --  anywhere             anywhere            
ufw-reject-output  all  --  anywhere             anywhere            
ufw-track-output  all  --  anywhere             anywhere            

Chain ufw-after-forward (1 references)
target     prot opt source               destination         

Chain ufw-after-input (1 references)
target     prot opt source               destination         

Chain ufw-after-logging-forward (1 references)
target     prot opt source               destination         

Chain ufw-after-logging-input (1 references)
target     prot opt source               destination         

Chain ufw-after-logging-output (1 references)
target     prot opt source               destination         

Chain ufw-after-output (1 references)
target     prot opt source               destination         

Chain ufw-before-forward (1 references)
target     prot opt source               destination         

Chain ufw-before-input (1 references)
target     prot opt source               destination         

Chain ufw-before-logging-forward (1 references)
target     prot opt source               destination         

Chain ufw-before-logging-input (1 references)
target     prot opt source               destination         

Chain ufw-before-logging-output (1 references)
target     prot opt source               destination         

Chain ufw-before-output (1 references)
target     prot opt source               destination         

Chain ufw-reject-forward (1 references)
target     prot opt source               destination         

Chain ufw-reject-input (1 references)
target     prot opt source               destination         

Chain ufw-reject-output (1 references)
target     prot opt source               destination         

Chain ufw-track-input (1 references)
target     prot opt source               destination         

Chain ufw-track-output (1 references)
target     prot opt source               destination
Improve this question
4
  • 1
    Disabling the ufw service that manages the firewall doesn't disable the firewall itself, which is part of the kernel. Did you check that there are no firewall rules blocking the traffic?
    – David Schwartz
    Feb 22, 2014 at 0:18
  • @David Schwartz not 100% sure; iptables -L outputs a lot of stuff but no explicit port/address rules, nothing that would explain difference between #3 and #5
    – glagolig
    Feb 22, 2014 at 1:05
  • If iptables -L outputs a lot of stuff, then you have firewall rules, likely these are the issue.
    – David Schwartz
    Feb 22, 2014 at 1:08
  • @David Schwartz I updated the question with iptables -L output
    – glagolig
    Feb 22, 2014 at 1:19

1 Answer 1

Reset to default
0

I turned out my org's firewall was blocking outgoing connections to those ports (22000 and others I tried.)

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .