Transcript PPT Version
Modification Proposals to Current TURN Spec Mikael Latvala Company Confidential 1 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials One Motivating Use Case Home Network Home Gateway Internet Remote Network The Internet Remote Network Company Confidential 2 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Problem Statement #1 • Restriction how TURN can be used (draft-ietf-behave-turn-05.txt) “A successful Allocate transaction just reserves a transport address on the TURN server. Data does not flow through an allocated transport address until the TURN client asks the TURN server to open a permission, which is done with a Send Indication. While the client can request more than one permission per allocation, it needs to request each permission explicitly and one at a time. This insures that a client can't use a TURN server to run a traditional server, and partially protects the client from DoS attacks. “ • Particular problems for home network • Home owner cannot know beforehand from which IP address (external IP address) s/he is going to access the home network • Even if home owner did magically know all the external IP addresses, most of the home automation and many AV based device would not be able to request such permissions, because there are no mechanisms how home owner could tell the devices what these external IP addresses are Company Confidential 3 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Problem Statement #2 • Restriction how ports are allocated (draft-ietf-behave-turn-05.txt) “The server SHOULD only allocate ports in the range 1024-65535. “ • The document should not take a stand on how TURN is used. • This is a deployment issue and must left up to individual entity to decide whether such restrictions should be enforced Company Confidential 4 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials Change proposals 1. Allow TURN client to disable/enable permission functionality in TURN server • Add new attribute PERMISSION which can have following values • • • Address dependent Address/port dependent (does someone really need this?) Disabled 2. Change/remove appropriate sections in the spec to reflect the proposed change in 1. • E.g. in 7.2.2 (there are other sections too) • “If a server receives a UDP packet on an allocated UDP transport address, it checks the permissions associated with that allocation. If the source IP address of the UDP packet matches one of the permissions (the source port is not used), the UDP packet is accepted. Otherwise, it is discarded. If the packet is accepted, it is forwarded to the client as described below.” 3. Remove the following paragraph in 6.2.1.4 • “The server SHOULD only allocate ports in the range 1024-65535. This is one of several ways to prohibit relayed transport addresses from being used to attempt to run standard services.” Company Confidential 5 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials