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Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 2326 (Obsoleted by RFC 7826) -- Obsolete informational reference (is this intentional?): RFC 3205 (Obsoleted by RFC 9205) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group M. Blanchet 3 Internet-Draft Viagenie 4 Intended status: Informational July 4, 2012 5 Expires: January 5, 2013 7 Implications of running Internet over ports 80 and 443 8 draft-blanchet-iab-internetoverport443-00.txt 10 Abstract 12 Users are often connected to Internet with very few outgoing ports 13 available, such as only port 80 and 443 over TCP. This situation has 14 many implications on designing, deploying and using IETF protocols, 15 such as encaspulating protocols within HTTP, difficulty to do traffic 16 engineering, quality of service, peer-to-peer, multi-channel 17 protocols or deploying new transport protocols. This document 18 describes the situation and its implications. 20 Status of this Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at http://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on January 5, 2013. 37 Copyright Notice 39 Copyright (c) 2012 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 55 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 3. Implications . . . . . . . . . . . . . . . . . . . . . . . . . 4 57 3.1. IETF Guidance . . . . . . . . . . . . . . . . . . . . . . . 4 58 3.2. Trafic Policing . . . . . . . . . . . . . . . . . . . . . . 4 59 3.3. Deploying New Protocols . . . . . . . . . . . . . . . . . . 4 60 3.4. Overloading HTTP . . . . . . . . . . . . . . . . . . . . . 4 61 3.5. Increasing the rate of usage of IP addresses . . . . . . . 5 62 3.6. More Complex Operations . . . . . . . . . . . . . . . . . . 5 63 3.7. Inability to Deploy Applications and Protocols . . . . . . 5 64 3.8. Applications Become Only HTTP-based . . . . . . . . . . . . 5 65 3.9. Applications Need to Become Very Smart for Opening 66 Connection . . . . . . . . . . . . . . . . . . . . . . . . 6 67 3.10. Internet Transport . . . . . . . . . . . . . . . . . . . . 6 68 3.11. Should IETF Protocols Only Use HTTP Encapsulation . . . . . 6 69 4. Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . 6 70 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 71 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 72 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 73 8. Informative References . . . . . . . . . . . . . . . . . . . . 7 74 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 76 1. Introduction 78 A trend started many years ago has been to provide Internet access to 79 end-users with limited outgoing ports. The most constraint but 80 common case is to only have outgoing TCP port 80 and port 443 opened. 81 Port 80 is expected to carry HTTP and some middleboxes in the network 82 may block non-HTTP traffic on that port. Port 443 is often less 83 policed than port 80 based on the assumption that it is carrying 84 encrypted traffic. However, enterprise firewalls sometimes verify 85 the use of TLS/SSL on port 443. 87 A consequence of this trend is that Internet statistics show 88 [Labovitz] that a majority of the Internet traffic is over port 80 89 and 443. And the concentration on these ports are further increasing 90 every year. 92 While the purpose of this document is not to find or judge the 93 reasons why providers (in the large sense of providing) are blocking 94 all outgoing ports except very few, a few known reasons can be 95 listed, while no opinion on the validity is expressed: 96 o Users only need HTTP anyway. Now email and chat is over HTTP. 97 o Less number of ports means easier control over shadow traffic. 98 o Provider wants to control, verify, police all outgoing traffic. 100 A consequence for the enterprise or non-HTTP application service 101 provider is that there are very few ways to offer a service to its 102 end-users. For example, an application (VoIP, ssh, jabber, ftp, ...) 103 provider need to use an additional IP address and to bind its 104 application server to the port 443 to make sure its users can reach 105 it whatever the characteristics of the access network the nomadic 106 users are attaching to. The other way is to build a tunnel such as 107 VPN to the service infrastructure and then tunnel all application 108 traffic to that tunnel. Obviously for the same reason, the tunnel 109 server itself has to be bound on port 443. 111 From the application developer point of view, HTTP framework is often 112 chosenfor its own benefits with or without the limited outgoing ports 113 deployment considerations, as discussed in 114 [I-D.tschofenig-post-standardization]. 116 2. Terminology 118 This document uses the term provider in a large sense of some 119 organization offering the Internet access to users. For example, a 120 provider in this document includes coffee shop wifi access, guest 121 access in various public places and networks, hotel networks, 122 enterprise guest access networks, as well as traditional providers 123 such as broadband, mobile and wifi network established large 124 providers. 126 3. Implications 128 This section lists some implications of this situation. 130 3.1. IETF Guidance 132 IETF provided guidance about the use of HTTP and port 80. For 133 example, [RFC3205] recommended to use different ports than 80 for new 134 services, even when HTTP encapsulation was used. This guidance may 135 need to be revisited. 137 This situation further complicates the Internet transparency, end-to- 138 end and hourglass model, as discussed in [RFC2775],[RFC3234] and 139 [RFC4924]. 141 3.2. Trafic Policing 143 If all traffic goes over one or two ports, then it is more difficult 144 to differentiate delay sensitive traffic to bulk traffic while 145 applying policies on forwarding engines at the transport level. The 146 policing nodes on the network haveto open the application payload. 147 For example, for Motion-JPEG over http, parsing the HTTP headers is 148 needed to discover that this data is streaming. 150 3.3. Deploying New Protocols 152 If port 80 and 443 are the only ports opened, then given that 153 middleboxes in networks are inspecting packets and validate HTTP 154 traffic, then a new protocol not based on HTTP and requiring a 155 different transport port or protocol is difficult, while impossible, 156 to deploy as is. 158 3.4. Overloading HTTP 160 Another consequence of this situation is that protocols and data go 161 over HTTP. HTTP is defined with a specific set of requirements and 162 is implemented in a solution set that is far from the IP layer. It 163 uses TCP transport, has multiple ascii headers in the payload to be 164 parsed, has state, etc. However, the HTTP protocol is being revised 165 [RFC6455][httpbis] related to some of these new requirements. 167 3.5. Increasing the rate of usage of IP addresses 169 If an organization has N different services where each one takes a 170 different port, then, in the context of its users only able to use 171 outgoing port 80/443, the organization has to use N IP addresses, one 172 for each service and bind the service on port 443 (or 80) on that IP 173 address. Therefore, the organization increases the rate of its usage 174 of IP addresses. Since IPv4 addresses are almost exhausted, this 175 situation adds pain to the IPv4 address exhaustion. IPv6 addresses 176 are almost limitless to this issue, but having too many IPv6 177 addresses on the same server to support the services add complexity 178 to the operations. 180 3.6. More Complex Operations 182 As a network operator likes to monitor traffic to engineer and 183 troubleshoot the network, it cannot do anymore by only looking at the 184 ports used by the traffic. For example, a peak traffic from a source 185 node that always uses a single outgoing port for all its traffic, may 186 be a video call or video streaming or file copy or a virus related 187 traffic or torrent or ... Therefore, the network operations is blind 188 to what the traffic is, unless the monitoring is at done within the 189 application payload. 191 3.7. Inability to Deploy Applications and Protocols 193 A good example of limitations to deploy applications and protocols 194 are IP cameras. These devices send video streams to outside. While 195 a typical protocol stack would use RTP/RTSP for this purpose, often 196 the only way to successfully send the stream in all cases is to 197 encapsulate it over HTTP using Motion JPEG or other coding over HTTP. 198 Similar issues also happen for interactive applications. The 199 constraint of the transport protocol to use may have an important 200 impact on the application design and behavior. 202 3.8. Applications Become Only HTTP-based 204 From the application developer point of view, the most garanteed way 205 to get its outgoing traffic from the client host to the Internet 206 (servers) is to carry its application data and protocols over HTTP 207 over port 80 and/or 443. This is, whatever the type of traffic, such 208 as gaming, voice, video, file transfer, augmented reality, 3D, ..., 209 with a wide set of different characteristics. Within the HTTP 210 framework, the Websocket Protocol[RFC6455] is one way to support the 211 variety of applications over HTTP. 213 3.9. Applications Need to Become Very Smart for Opening Connection 215 Skype is a good illustration of a deployable application that works 216 in most cases. Analysis of Skype behavior [ColumbiaSkype] shows 217 Skype is trying to open outgoing ports, and when not possible, 218 defaults to port 80 or 443 as last resort. Therefore, this 219 illustrates that a successful deployable application should use 220 similar techniques with the last resort being port 80 or 443. That 221 also means the other peer of the communication must be bound to the 222 same 80 or 443 port. This application behavior may require to have 223 standardized ways of handling encapsulation over 80/443 for realtime 224 applications. 226 3.10. Internet Transport 228 Written differently, this situation can be described as the Internet 229 can only run with a single transport protocol(TCP) and two transport 230 ports(80,443). Given that some deployments have HTTP-aware 231 middleboxes on those ports, then the Internet can only run "reliably" 232 over a single transport protocol (HTTP) and a single transport port 233 (443). 235 3.11. Should IETF Protocols Only Use HTTP Encapsulation 237 Given above, should the IETF only design protocols over HTTP? Should 238 all current protocols be redesigned to be carried over HTTP? (more a 239 question to debate than an affirmation...) 241 For example, 3GPP and MPEG produced the Dynamic Adaptive Streaming 242 over HTTP(DASH) protocol[DASH] where one of the reasons is related to 243 firewalls and NAT traversal. This new protocol is intended to 244 replace the RTSP [RFC2326] protocol. 246 Websockets[RFC6455] is a standardized way to encapsulate subprotocols 247 within HTTP and therefore multiplexing the various application 248 protocols within HTTP. 250 [I-D.tschofenig-post-standardization] also discuss about this issue. 252 4. Mitigation 254 IPv6 could be seen as a way to mitigate that problem. As discussed 255 above, the reasons why access providers or enterprises are limiting 256 outgoing ports are not related to IPv4 address exhaustion or IPv4 257 itself. 259 However, on the server side of the connections, given the large IPv6 260 address space available per server, IPv6 could be used to partly 261 mitigate the problem by having, on a single server, each service 262 bound to a different IPv6 address while using the same transport port 263 80. 265 5. Security Considerations 267 This document does not specify a new protocol. However, it does 268 highlight security impacts of the current Internet access. 270 6. IANA Considerations 272 This document has no actions for IANA. 274 7. Acknowledgements 276 Dave Thaler, Hannes Tschofenig, Brian Carpenter, Bernard Adoba have 277 provided input and suggestions to this document. 279 8. Informative References 281 [ColumbiaSkype] 282 Baset, S. and H. Schulzrinne, "An Analysis of the Skype 283 Peer-to-Peer Internet Telephony Protocol", . 286 [DASH] "ISO/IEC 23009-1:2012 Information technology -- Dynamic 287 adaptive streaming over HTTP (DASH) -- Part 1: Media 288 presentation description and segment formats", . 292 [I-D.tschofenig-post-standardization] 293 Tschofenig, H., Aboba, B., Peterson, J., and D. McPherson, 294 "Trends in Web Applications and the Implications on 295 Standardization", draft-tschofenig-post-standardization-02 296 (work in progress), May 2012. 298 [Labovitz] 299 Labovitz, C., "Internet Traffic and Content 300 Consolidation", March 2010, 301 . 304 [RFC2326] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time 305 Streaming Protocol (RTSP)", RFC 2326, April 1998. 307 [RFC2775] Carpenter, B., "Internet Transparency", RFC 2775, 308 February 2000. 310 [RFC3205] Moore, K., "On the use of HTTP as a Substrate", BCP 56, 311 RFC 3205, February 2002. 313 [RFC3234] Carpenter, B. and S. Brim, "Middleboxes: Taxonomy and 314 Issues", RFC 3234, February 2002. 316 [RFC4924] Aboba, B. and E. Davies, "Reflections on Internet 317 Transparency", RFC 4924, July 2007. 319 [RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol", 320 RFC 6455, December 2011. 322 [httpbis] "Hypertext Transfer Protocol Bis (httpbis)", 323 . 325 Author's Address 327 Marc Blanchet 328 Viagenie 329 246 Aberdeen 330 Quebec, QC G1R 2E1 331 Canada 333 Email: Marc.Blanchet@viagenie.ca 334 URI: http://viagenie.ca