Has anyone seen a problem where two machines can communicate on a UDP
socket connection just fine but the same two processes on the same two
machines fail to connect (connect timeout) when trying to communicate
with TCP? Any ideas where to look? The network is a mess, with
machines routed through three different switches, but the problem even
affects two processes on the same machine trying to connect to each
other.

It's very late and I'm really tired so if there is something I'm
missing, maybe one of you has an idea or has experienced something
similar before?

Thanks for any pointers you may have.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443

On Sat, Mar 6, 2010 at 10:13 PM, Robin Scher robin@uberware.net wrote: > Thanks for any pointers you may have. >

iptables or other local firewall?

Wireshark and tcpdump are probably your best bet to suss it out..

good luck, -barry

What operating system?

------Original Message------ From: Robin Scher To: StudioSysAdmins ReplyTo: discuss@studiosysadmins.com Subject: Problems with TCP Sent: Mar 6, 2010 3:13 AM

Has anyone seen a problem where two machines can communicate on a UDP socket connection just fine but the same two processes on the same two machines fail to connect (connect timeout) when trying to communicate with TCP? Any ideas where to look? The network is a mess, with machines routed through three different switches, but the problem even affects two processes on the same machine trying to connect to each other.

It's very late and I'm really tired so if there is something I'm missing, maybe one of you has an idea or has experienced something similar before?

Thanks for any pointers you may have.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443

This communication is for use by the intended recipient and contains information that may be privileged, confidential or trade secret under applicable law. If you are not the intended recipient, you are hereby formally notified that any use, copying or distribution of this email, in whole or part, is strictly prohibited. Please notify the sender by return email and delete this email from your system.

Has anyone seen a problem where two machines can communicate on a UDP socket connection just fine but the same two processes on the same two machines fail to connect (connect timeout) when trying to communicate with TCP?

• is the port open on the receiving end? (netstat -ant | grep LIST)
• any packet filtering on either side?
• are they in the same L2 network?
• is nscd running? kill it if so.
• syslog have anything?

Any ideas where to look? The network is a mess, with machines routed through three different switches, but the problem even affects two processes on the same machine trying to connect to each other.

• packets flowing threw multiple switches shouldn't be an issue if you are loop and error free. whatever L2 issues you may have would affect all protocols. check the port counters on the switches along the path, look for errors.
• you may be looking at two different issues, no matter how foobar'd your network may be, processes on the same machine should be able to communicate with each other, even without a network. If this is one of the two machines you speak of above, you may want to focus on it, if it can't talk to itself.

if the process is using port 444, run tcpdump on both machines:

tcpdump -nv port 444 and host MACHINE1 or MACHINE2 -r /tmp/cap1.pcap

then attempt the connection. after it times out kill the tcpdump, send the contents of the file, or paste them here, it should only be a few lines.

good luck! -g

Sorry, should have specified Machines are running Windows 7 Pro 64 bit.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443 -----Original Message----- From: studiosysadmins-discuss-bounces@mailman.studiosysadmins.com [mailto:studiosysadmins-discuss-bounces@mailman.studiosysadmins.com] On Behalf Of Anthony Lopez Sent: Saturday, March 06, 2010 9:36 AM To: 'discuss@studiosysadmins.com' Subject: Re: Problems with TCP

What operating system?

------Original Message------ From: Robin Scher To: StudioSysAdmins ReplyTo: discuss@studiosysadmins.com Subject: Problems with TCP Sent: Mar 6, 2010 3:13 AM

Has anyone seen a problem where two machines can communicate on a UDP socket connection just fine but the same two processes on the same two machines fail to connect (connect timeout) when trying to communicate with TCP? Any ideas where to look? The network is a mess, with machines routed through three different switches, but the problem even affects two processes on the same machine trying to connect to each other.

It's very late and I'm really tired so if there is something I'm missing, maybe one of you has an idea or has experienced something similar before?

Thanks for any pointers you may have.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443

This communication is for use by the intended recipient and contains information that may be privileged, confidential or trade secret under applicable law. If you are not the intended recipient, you are hereby formally notified that any use, copying or distribution of this email, in whole or part, is strictly prohibited. Please notify the sender by return email and delete this email from your system.

From: studiosysadmins-discuss-bounces@mailman.studiosysadmins.com [studiosysadmins-discuss-b Subject: RE: Problems with TCP

Sorry, should have specified Machines are running Windows 7 Pro 64 bit.

there's your answer. 8)

you can use wireshark instead of tcpdump on windows, and the netstat command from cmd shell, the switches would be different tho. i wouldn't be surprised if your dealing with some os bug tho. 8)

-g

You should check and make sure the windows firewall isn't blocking it or you can try running a "netsh winsock reset"

----- Original Message ----- From: studiosysadmins-discuss-bounces@mailman.studiosysadmins.com studiosysadmins-discuss-bounces@mailman.studiosysadmins.com To: discuss@studiosysadmins.com discuss@studiosysadmins.com Sent: Sat Mar 06 13:36:14 2010 Subject: RE: Problems with TCP

Sorry, should have specified Machines are running Windows 7 Pro 64 bit.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443 -----Original Message----- From: studiosysadmins-discuss-bounces@mailman.studiosysadmins.com [mailto:studiosysadmins-discuss-bounces@mailman.studiosysadmins.com] On Behalf Of Anthony Lopez Sent: Saturday, March 06, 2010 9:36 AM To: 'discuss@studiosysadmins.com' Subject: Re: Problems with TCP

What operating system?

------Original Message------ From: Robin Scher To: StudioSysAdmins ReplyTo: discuss@studiosysadmins.com Subject: Problems with TCP Sent: Mar 6, 2010 3:13 AM

Has anyone seen a problem where two machines can communicate on a UDP socket connection just fine but the same two processes on the same two machines fail to connect (connect timeout) when trying to communicate with TCP? Any ideas where to look? The network is a mess, with machines routed through three different switches, but the problem even affects two processes on the same machine trying to connect to each other.

It's very late and I'm really tired so if there is something I'm missing, maybe one of you has an idea or has experienced something similar before?

Thanks for any pointers you may have.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443

This communication is for use by the intended recipient and contains information that may be privileged, confidential or trade secret under applicable law. If you are not the intended recipient, you are hereby formally notified that any use, copying or distribution of this email, in whole or part, is strictly prohibited. Please notify the sender by return email and delete this email from your system.

This communication is for use by the intended recipient and contains information that may be privileged, confidential or trade secret under applicable law. If you are not the intended recipient, you are hereby formally notified that any use, copying or distribution of this email, in whole or part, is strictly prohibited. Please notify the sender by return email and delete this email from your system.

If it is Windows 7 operating system, try disabling the User Account Control (UAC) and the firewall. Also not sure whether inbound connection limit has reached, it is 20 for Windows 7.
Reference link: http://www.winsupersite.com/win7/win7_skus_compare.asp

Cheers,
Adarsh
http://www.linkedin.com/in/adarsh

Hey Robin,

Rotofactory is running our entire Smedge Farm on Windows 7 Pro 64 now and I have not had any problems with it so far. That includes some systems being 2 switches away, thought the primary farm all sit on the same Switch.

I agree with the suggestion here. Throw wireshark on one of the machines and see what it finds, preferably the machine that can't even talk to itself over these ports. Sounds like a firewall or something else blocking the port.

And I would also suggest just for the purposes of testing we eliminate the network as the issue by bringing the two machines together on the same switch (if that's possible), just to verify that the problem persists so that we know its system based and not a network issue.

Wes

-----Original Message----- From: studiosysadmins-discuss-bounces@mailman.studiosysadmins.com [mailto:studiosysadmins-discuss-bounces@mailman.studiosysadmins.com] On Behalf Of Robin Scher Sent: Saturday, March 06, 2010 1:36 PM To: discuss@studiosysadmins.com Subject: RE: Problems with TCP

Sorry, should have specified Machines are running Windows 7 Pro 64 bit.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443 -----Original Message----- From: studiosysadmins-discuss-bounces@mailman.studiosysadmins.com [mailto:studiosysadmins-discuss-bounces@mailman.studiosysadmins.com] On Behalf Of Anthony Lopez Sent: Saturday, March 06, 2010 9:36 AM To: 'discuss@studiosysadmins.com' Subject: Re: Problems with TCP

What operating system?

------Original Message------ From: Robin Scher To: StudioSysAdmins ReplyTo: discuss@studiosysadmins.com Subject: Problems with TCP Sent: Mar 6, 2010 3:13 AM

Has anyone seen a problem where two machines can communicate on a UDP socket connection just fine but the same two processes on the same two machines fail to connect (connect timeout) when trying to communicate with TCP? Any ideas where to look? The network is a mess, with machines routed through three different switches, but the problem even affects two processes on the same machine trying to connect to each other.

It's very late and I'm really tired so if there is something I'm missing, maybe one of you has an idea or has experienced something similar before?

Thanks for any pointers you may have.

Robin Scher, Smedge Master robin@uberware.net +1 (213) 448-0443

This communication is for use by the intended recipient and contains information that may be privileged, confidential or trade secret under applicable law. If you are not the intended recipient, you are hereby formally notified that any use, copying or distribution of this email, in whole or part, is strictly prohibited. Please notify the sender by return email and delete this email from your system.