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Old 11-29-2000, 03:17 PM   #1
vlad
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Registered: Nov 2000
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Please help.
In our project I need to establish TCP connection between two sockets on the same host. Normally it should be done over the "lo" local loop. But due to the run-time search for the IP of the destination, - I have to use "eth0" and use "dot IP" notation for the host.
DOesn't work.
Any system services, like ping, between same host sockets don't work. System (kernel) doesn't allow through.
How to configure the system to allow such connection ?
I appreciate any suggestions.

Vlad.
 
Old 12-15-2000, 04:36 AM   #2
TK Tech
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[QUOTE]Originally posted by vlad
Please help.
In our project I need to establish TCP connection between two sockets on the same host. Normally it should be done over the "lo" local loop.[QUOTE]

Really ? How did you do this ?

Quote:
But due to the run-time search for the IP of the destination, - I have to use "eth0" and use "dot IP" notation for the host.
DOesn't work.
Any system services, like ping, between same host sockets don't work. System (kernel) doesn't allow through.
How to configure the system to allow such connection ?
I appreciate any suggestions.
Vlad.
Which distribution are U using ?
Did your network card is properly installed ?
Are your PC connected per-to-per or from part of a Intranet ?

Sorry,....just to make sur before to solve....

Good luck !
 
Old 12-15-2000, 10:34 PM   #3
vlad
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Wink Done

After much investigation I found the problem.

First, to clarify what was going on:
normaly, when creating connection to the same host you use a "localhost" or "127.0.0.1" and this is routed to the "lo" interface.
In the destributed application, client is getting IP in the run-time and this IP may become the same host.
In this case the following happens: Linux kernel (RedHat 6.2 kernel 2.2.16) providing full internet address, like 205.144.333.222 still identifies it as a local address and sends it over the "lo" as if it were 127.0.0.1 !

Here is a bug :
this host has it's own firewall which does not allow exterior internet IP over the loop !
By adding the line to ipchains
/sbin/ipchains -A input -s 205.144.333.222 -i lo -j ACCEPT
I fixed the problem.

Thanks for interest
Vlad
 
  


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