View Full Version : Cloud and using external services

22-Jun-2016, 04:08 AM
Just to ask a general question

Do any of the major hosting providers replace any restrictions on making calls to external services/ports from virtual servers you have hosted with them ?

Back in the early days of shared web hosting and hosted servers before things became fluffy and white you may not for example connect to an SMTP server that was outside the hosting company. I think they did this to help prevent email relay spam

You may also be prevented from making http calls outside of your domain etc in case someone had hacked your site and wanted to siphon data off etc

In a modern connected world of web services etc do these kinds of practices still hold true ? are most TCP outgoing ports closed by default ?

eg from a DF webapp hosted on AWS can I call a webservice at someexternalcompany.com via port 80 and send an email via smtp.outsideofaws.com port 25/437 etc etc

Mike Cooper
22-Jun-2016, 07:24 AM
In my experience, the instance that was provided was fairly open, meaning that it was up to me to close out various ports. I use an external smtp on my cloud and have no issues.

FYI, my instance is hosted by www.netelligent.ca Very happy with their pricing and their service.


22-Jun-2016, 12:27 PM
We host at AWS and have not found anything blocked.

22-Jun-2016, 09:48 PM
AWS has what is called Security Groups that allow you control both Inbound and Outbound ports allowed. You can even go so far as restrict the IP address range for the port, for instance RDP port (3389) to only your own IP address or a corporate IP address range. There are no restrictions unless you set them up yourself. The normal default security group settings is to allow RDP (Open =all IP addresses), HTTP (port 80) and HTTPS (443).

22-Jun-2016, 09:52 PM
Hi Chuck,
Is security group also how you group a couple of instances together so they can share resources like an SQL server?

22-Jun-2016, 10:24 PM
No that is the VPC.