User Tools

Site Tools


CalTel Port Forwarding & Blocking

Sending Email Through Another Provider

As an anti-spam policy, you MUST use a secure and authenticated method to send email through a third party email provider. In fact, there are almost no mail providers today that will even allow you to send email via an unsecured method. To use an email client like Outlook or Thunderbird, you will need to use their SMTP SUBMISSION port (tcp 587) or SMTPS (tcp 465) service. You may also consider using their webmail service. You cannot use outbound email service if it is only hosted on port 25. Port 25 would allow a compromised PC to send out virtually unlimited spam. See Hosting A Mail Server below.

I have a new <insert gadget>, do I need to forward ports?

In most situations, probably not.

First, very few electronics in today's world require port forwarding. There are even many things that claim to need port forwarding but don’t (i.e Skype, PS4, Xbox, Sling Box, and at&t Microcell) should all work out of the box. Plug it in, and try it! If the device does not work as you think it should please call us and we will help with troubleshooting your device.

Sometimes devices may have really picky network settings, and will require you to purchase a specific compatible router for them to work properly. We can help you make that decision and then re-configure your equipment when the time comes so that your device works reliably.

Hosting your own server?

CalTel by default blocks just a couple of really common server ports, like HTTP and SSH. We started doing this recently to harden our overall network against being an easy and soft target for massive DDoS attacks.

It is trivial for us to open these ports for you, and also we can assist you in forwarding these ports in your DSL modem or Router so that you can run your server. This is very common with many legacy home surveillance systems or cameras.

Hosting a Mail Server

We block outbound port 25 for two reasons:

  1. Prevent home computers infected with spyware from becoming spam bots. A single computer can easily pump out 100,000 spam or virus messages per hour.
  2. Prevent an improperly setup mail server from blasting out 100,000 spam messages per hour.

Even if you do setup your mail server securely, we STRONGLY recommend that you do NOT do this. We suggest looking into setting up a google apps account. You literally must be an email expert to host a mail server correctly, and even then, much of the mail you send will probably be deleted by spam engines because they will know the mail is originating from a broadband account.

knowledge_base/troubleshooting/portforwardingblocking.txt · Last modified: 2020/08/07 14:16 by ddegen