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Unable to connect telnet 25

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Unable to connect telnet 25 - 15.Jun.2008 3:55:58 AM

lkvenkatesh

Posts: 2
Joined: 15.Jun.2008
Status: offline

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

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RE: Unable to connect telnet 25 - 15.Jun.2008 1:16:49 PM

uemurad

Posts: 5321
Joined: 7.Jan.2004
From: California, USA
Status: offline

That IP address isn't open to inbound port 25. It doesn't respond to ping, but that doesn't really mean anything since you can block it separately.

This is a networking issue at this point. You first have to determine if you can communicate at all to that IP address. That you need to troubleshoot first with your ISP and second with your border devices (routers and firewalls) to make sure routing is configured correctly and then if port 25 is open.

Typically you'd want to NAT the public IP address to your private address through your firewall/router and not have the second NIC.

< Message edited by uemurad -- 15.Jun.2008 1:17:59 PM >

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Regards,

Dean T. Uemura
Microsoft MVP - Exchange
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to lkvenkatesh)

Post #: 2

RE: Unable to connect telnet 25 - 3.Jul.2008 4:48:56 AM

lkvenkatesh

Posts: 2
Joined: 15.Jun.2008
Status: offline

Hi,

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.,

(in reply to uemurad)

Post #: 3