Tunneling protocol
Encyclopedia : T : TU : TUN : Tunneling protocol
| Layer | Protocols |
|---|---|
| Application | DNS, TLS/SSL, TFTP, FTP, HTTP, IMAP, IRC, NNTP, POP3, SIP, SMTP, SNMP, SSH, TELNET, BitTorrent, RTP, rlogin, … |
| Transport | TCP, UDP, DCCP, SCTP, IL, RUDP, |
| Network | IP (IPv4, IPv6), ICMP, IGMP, ARP, RARP, … |
| Link | Ethernet, Wi-Fi, Token ring, Point-to-Point Protocol>PPP, SLIP, FDDI, ATM, DTM, Frame Relay, SMDS, … |
A tunneling protocol is a network protocol which encapsulates one protocol or session inside another. Protocol A is encapsulated within protocol B, such that A treats B as though it were a data link layer. Tunneling may be used to transport a network protocol through a network which would not otherwise support it. Tunnelling may also be used to provide various types of VPN functionality such as private addressing.
Examples include:
Datagram-based:
- L2TP (Layer 2 Tunneling Protocol)
- MPLS (Multi-Protocol Label Switching)
- GRE (Generic Routing Encapsulation)
- GTP (GPRS Tunnelling Protocol)
- PPTP (Point-to-Point Tunneling Protocol)
- PPPoE (point-to-point protocol over Ethernet)
- PPPoA (point-to-point protocol over ATM)
- IP in IP Tunneling (RFC 1853)
- IPsec
- IEEE 802.1Q (Ethernet VLANs)
- DLSw (SNA over IP)
- XOT (X.25 datagrams over TCP)
- 6to4 (IPv6 over IPv4 as protocol 41)
- Teredo (IPv6 over UDP over IPv4)
- Anything In Anything (AYIYA; e.g. IPv6 over UDP over IPv4, IPv4 over IPv6, IPv6 over TCP IPv4, etc.)
SSH tunneling
SSH is frequently used to tunnel insecure traffic over the Internet in a secure way. For example, Windows machines can share files using the Samba (SMB) protocol, which is not encrypted. If you were to mount a Windows filesystem remotely through the Internet, someone snooping on the connection could see your files.
So to mount a SMB file system securely, one can establish an SSH tunnel that routes all SMB traffic to the fileserver inside an SSH-encrypted connection. Even though the SMB traffic itself is insecure, because it travels within an encrypted connection it becomes secure.
Tunneling can also be used to bypass a system firewall.
See also
- Tunnel Broker
- Virtual Private Network (Tunneling)
References
- This article was originally based on material from the Free On-line Dictionary of Computing, which is [Foldoc licenselicensed] under the GFDL.
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.