ISG recommends using IMAP protocol to access your mailbox when not using the webmail application. This is especially important if you plan to use multiple devices, such as a desktop computer, a laptop, and a smartphone.
ISG supports both IMAP and IMAPS (SSL) protocols. Most mail clients and devices are compatible with IMAPS and SSL encryption. We recommend SSL since your email username and password, as well as any sensitive content, will be encrypted. Note that you will likely receive a SSL warning that the certificate is untrusted. This is normal because our servers use a SSL certificate in the isgsoftware.net domain and it will not match your domain. If prompted, you should select to ignore SSL warnings and accept the certificate.
What is the difference?
When using POP3 protocol, typically the mail client will download all messages from your inbox to the computer or device that is accessing it. The main drawback to this is that if you access your mail from multiple devices, your email will be scattered among them. You will not be able to access any previously read emails via the webmail application. Additionally, you will have to ensure that you are backing up your email on each device.
IMAP protocol keeps your email messages on the server and downloads copies as you read them. Since your email is stored on the server, any device or application can access your messages. You can also create folders (and subfolders) to keep your email organized.
ISG uses the standard TCP/IP ports for mail services:
POP3 - port 110
POP3S (SSL) - port 995
IMAP - port 143
IMAPS - port 993