avast has and is using servers all around the world.
Some of them are their own while others are rented.

Some of the servers that avast is using can be found in the file servers.def
Keep in mind that the domain of the servers for update will change.
Today it can be http://w9448963.ivps9tiny.u.avast.com/ivps9tiny while tomorrow it is http://w8873214.ivps9tiny.u.avast.com/ivps9tiny
This is done for security reasons.