Blog: ISP

This applies to any e-mail accounts setup to get e-mail using POP3. 

A customer that uses an e-mail account provided by their ISP for work was frequently having new e-mail rejected because the mailbox was full.  Looking at the storage space on the ISP’s website, they were limited to only 20 MB of e-mail storage.  They usually would have to delete e-mails on the ISPs website in order to receive new e-mails again.  The customer also had been setup to connect to the ISP’s server using POP3 in Microsoft Outlook, and Microsoft Outlook was configured to save e-mails to a local PST file on the hard drive.

In Microsoft Outlook, open the “Account Settings” for your e-mail account.  Click on “More Options” to view more settings and select the “Advanced” tab. [more]

With POP3, you can give Microsoft Outlook the option to “Leave a copy of messages on the server”.  If this is unchecked, new e-mails received at the ISP remain there until Microsoft Outlook downloads them.  After it downloads the e-mail, the e-mail is deleted on the ISP’s mail account.

An important thing to remember is that the local PST file needs to be backed up regularly because all e-mails will be lost if the PC crashes, PST file becomes corrupt, or you want to change PCs.


A customer had switched their POP3 email and internet service to a new ISP. Which required them to change their POP3 and SMTP settings on a couple of users' iPhones. The users were able to receive but not send email.  When initially setting up POP3 on an iPhone it requires adding the ISP's SMTP settings and then once it is configured changing it to AT&T’s which is there by default ( This change only has to be done if the SMTP server for the ISP is using port 25. This is because AT&T blocks port 25 on their data network for wireless and internet customers. Sometimes you can get them to unblock it for your account but that is rare.

One of the iPhone users also had a laptop that he only uses with an AT&T Express Card on the GPRS network. He could receive but not send email. Since he was accessing his POP3 account via the AT&T data network port 25 was blocked. I entered “” for the  SMTP server just like for the iPhone and was then able to send.


It’s good to check with your Internet Service Provider (ISP) every once and a while to make sure there haven’t been any changes to their DNS servers.  I was recently working with a customer who was having a problem viewing a certain webpage.  Even though the webpage was valid, when the customer would try to access it, an “under construction” page would appear.  Troubleshooting revealed that when their DNS servers had to do a recursive query, they were getting invalid IP addresses from their ISP’s DNS servers.

I called the ISP’s tech support and the case was quickly escalated to tier 2.  When I received a call back, the engineer explained that the DNS servers that were entered for resolving recursive queries did not actually respond to queries, but were authoritative only. I was given a different pair of IP DNS server IP addresses to use for queries.  Once the change was made, the website displayed correctly.


One of our customers was having problems reported by their terminal server users last week where their remote core systems were being very slow and having disconnects.  In the past, they have rebooted routers, terminal server, and their domain controler to get it to working much better but eventually it would slow way down again.  After doing a reboot of the equipment last week, the users again reported that it was very, very, very slow a few days later.  There was a Symantec Premium Anti-spam process running last week that I thought to be the culprit, but it looked to be running okay on the DC this time. [more]

I decided that I had better check the Internet connection speed using a speed test from  Their results were an abysmal 53 kbps (this is in the dialup range folks).  I asked them to call their ISP and get them to check the line.  They found problems with the cable modem (one, that it was very ancient) and replaced it.  After the hardware replacement, things are running much smoother.

In summary: It never hurts to perform an Internet speed test when things are running slowly.