SIP ALG can be both useful and a pain. This can become apparent when trying to setup a SIP connection to a PBX on the internet somewhere. Or alternatively, dialling into a local PBX from externally. Many do no realise that SIP ALG is enabled by default on most routers. Read more…
IPv6 is very easy to delegate to your customers if you are an ISP. This streamlines the way your customers connect to your provider edge and into the internet. Lets see the small topology for this tutorial: Here we have two routers for a basic configuration of IPv6 Prefix delegation. Read more…
With the IPv4 public address space running out very fast, we will soon be adopting IPv6. Many enterprises and ISP’s are already using IPv6 in their core networks. When the rest of the world come to adopt this new technology, you will need to know how to configure interfaces and Read more…
As we have exhausted all IPv4 addresses it was decided to implement NAT in a lot of areas of the internet. You are probably reading this sat behind a router that is performing a variation of NAT. NAT’s purpose is to translate addresses. The main example of this would be Read more…
There may come a time where you need to limit the speed of a connection coming through a router. This could be part of an internal network or part of and ISP’s network. I am going to demonstrate this on an ISP topology where we are limiting the customers speed Read more…
Many companies will have internal servers that need to be accessed outside of the organisation. These could be web servers or mail servers. Here I will show how to configure a Cisco router to map your internal servers to an external IP provided by your ISP using Network Address Translation Read more…