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unable to connect telnet 25

I have exchange 2003 installed on windows 2003 enterprise edition which is hosted to receive and send email internally its really working good and but externally through a smtp the problem is i can telnet my exchange server with private ip but cant telnet with my public ip?

My system have 2 nic card one for private ip and another for public ip
I have configured routing and remote access and i have enable SMTP 25 WAN properties. I have attached screen shot of that for your reference.

private ip of my exchange is 192.168.1.100
public ip is 122.166.7.159

if i telnet 192.168.1.100 i get this error
C:\>telnet 192.168.1.100 25
220 exchange.shifaconstructions.local Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959
ready at sun, 15 jun 2008 12:33:55 +0530

if i telnet on my public ip i get the response

c:\telnet 122.166.7.159 25
Connecting To 122.166.7.159...Could not open connection to the host, on port 25: Connect failed

please let me know the sol

thnx
smtp.JPG

DSchel01

Does the Exchange server use the IP address of the RRAS server as configure as its gateway server?

This would be a requirement just incase the Exchange server uses another gateway (or has no gateway set).

Dan

fishadr

Where is the public (internet) computer you are using to run the tests. You mention that the Exchange system is working correctly, I would therefore think that there is something blocking your port 25 connection from your client computer to the Exchange server's public IP address.

Have you any firewall software installed that is blocking port 25 communicaitons?
Can you connect to any other companis mail systems on port 25 (to prove that it is not your Exchange system/ client causing the problem)
Are there any other devices in between you and the Exchange public address that may be filtering or blocking the communications?

fishadr

How you getting on with this one - Need any more help?

Fahed_Ahmed_Shaik

ASKER

Hi fishadr,

Thanks for your reply, I found out my problem , by default my service provider blocked SMTP port 25. now my service provider given proper permission. now i can connect SMTP port 25 through telnet and email also sent and receive without any trouble.

regards,

venkatesh
invtsindia software pvt ltd.,

fishadr

This is a common problem - many ISP's block port 25 connections or restrict their usage. Using Telnet usually helps to diagnose if they are indeed doing so, or if the problem lies elsewhere.

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