Problem sending E-mail from my Network

Hi,

First, I would like to thank you in advance for giving your valuable time to help in solving my problem.

I have a network of around 100 users. I have total of three servers. 1) Win-2000 server for user authentication & Exchange on it. 2) Win-2000 with ISA Installed on it. 3) Win-2000 with ADC for the main server and it works as a database server.

I use Dialup account to upload my data to the internet and uses satellite link to download.

I have my company web site hosted as professionals.edu.sa on the webserver of the ISP. So I was looking to get email addresses for all our employees as xyz@professionals.edu.sa.

We requested the ISP to make 50 POP3 email addresses for all our employees. So they created these accounts. Now I want to use Microsoft Outlook 2003 to send and receive email's with this POP account.

I got POP3 & SMTP address from the ISP. Now the problem is I configured outlook. It receives the emails perfectly without any problem. When I say "Test account settings" it checks all the lines. OK. But when I try to send an email to someone at yahoo or hotmail or anyone else, my outlook stops sending the mail. And it gives an error message as

!Task mail.webcentric-sa.com Sending - Reported error. (0x80040210B). The operation timed out waiting for a response from the sending SMTP server.

I tried with a single machine with Dial-up connection to check my POP3 accounts. They worked perfectly with outlook.

Your ISP has better knowledge to answer their-own-setup questions. Ask them what kind of relay mechanism they are using, you might need to pop-first or auth-first.

I am in the process of getting some help from my ISP now.

But still I have a problem, I cannot ping to yahoo or any other site from my clients, whereas every client can browse the internet without any problem.

When I type nslookup command from any of my client, it shows only my local DNS server. I got the DNS server name and IP Address from my ISP.

Can you help me to add this secondary ISP DNS entry in my local DNS. So that whenever I say nslookup from my clients it should list my local DNS as well as My ISP DNS.