git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@4054 ec53bebd-3082-4978-b11e-865c3cabbd6b
This commit is contained in:
Johan Danielsson
1997-11-20 05:04:00 +00:00
parent 6d89dac5a9
commit ae7d687956
2 changed files with 46 additions and 48 deletions

View File

@@ -61,8 +61,8 @@ Abstract
.ti 0 .ti 0
Introduction Introduction
Kerberos is a protocol for authenticating parties communicating over Kerberos[RFC1510] is a protocol for authenticating parties
insecure networks. communicating over insecure networks.
Firewalling is a technique for achieving an illusion of security by Firewalling is a technique for achieving an illusion of security by
putting restrictions on what kinds of packets and how these are sent putting restrictions on what kinds of packets and how these are sent
@@ -72,8 +72,6 @@ between the internal (so called \*Qsecure\*U) network and the global (or
.ti 0 .ti 0
Definitions Definitions
types of firewalls: ...
client: the user, process, and host acquiring tickets from the KDC and client: the user, process, and host acquiring tickets from the KDC and
authenticating itself to the kerberised server. authenticating itself to the kerberised server.
@@ -86,16 +84,16 @@ client, for example telnetd.
Firewalls Firewalls
A firewall is usually placed between the \*Qinside\*U and the A firewall is usually placed between the \*Qinside\*U and the
\*Qoutside\*U and is supposed to protect the inside from the evils on \*Qoutside\*U networks, and is supposed to protect the inside from the
the outside. There are different kinds of firewalls. The main evils on the outside. There are different kinds of firewalls. The
differences are in the way they forward packets. main differences are in the way they forward packets.
.Ip 1 .Ip \(bu
The most straight forward type is the one that just imposes The most straight forward type is the one that just imposes
restrictions on incoming packets. Such a firewall could be described restrictions on incoming packets. Such a firewall could be described
as a router that just throws away packets that match some criteria. as a router that filters packets that match some criteria.
.Ip 2 .Ip \(bu
They may also \*Qhide\*U some or all addresses on the inside of the They may also \*Qhide\*U some or all addresses on the inside of the
firewall, replacing the addresses in the outgoing packets with the firewall, replacing the addresses in the outgoing packets with the
address of the firewall (aka network address translation, or NAT). NAT address of the firewall (aka network address translation, or NAT). NAT
@@ -108,7 +106,7 @@ There are also firewalls that does NAT both on the inside and the
outside (a server on the inside will see this as a connection from the outside (a server on the inside will see this as a connection from the
firewall). firewall).
.Ip 3 .Ip \(bu
A third type is the proxy type firewall, that parses the contents of A third type is the proxy type firewall, that parses the contents of
the packets, basically acting as a server to the client, and as a the packets, basically acting as a server to the client, and as a
client to the server (man-in-the-middle). If Kerberos is to be used client to the server (man-in-the-middle). If Kerberos is to be used
@@ -116,19 +114,17 @@ with this kind of firewall, a protocol module that handles KDC
requests has to be written. requests has to be written.
.in 3 .in 3
This type of firewall might also add extra trouble when used with This type of firewall might also cause extra trouble when used with
kerberised versions of protocols that the proxy understands, in kerberised versions of protocols that the proxy understands, in
addition to the ones mentioned below. addition to the ones mentioned below. This is the case with the FTP
Security Extensions [RFC2228], that adds a new set of commands to the
This is the case with the FTP Security Extensions [RFC2228], that adds FTP protocol [RFC959], for integrity, confidentiality, and privacy
a new set of commands to the FTP protocol [RFC959], for integrity, protecting commands. When transferring data, the FTP protocol uses a
confidentiality, and privacy protecting commands. When transferring separate data channel, and an FTP proxy will have to look out for
data, the FTP protocol uses a separate data channel, and an FTP proxy commands that start a data transfer. If all commands are encrypted,
will have to look out for commands that start a data transfer. If all this is impossible. A protocol that doesn't suffer from this is the
commands are encrypted, this is impossible. Telnet Authentication Option [RFC1416] that does all authentication
and encryption in-bound.
An example of a protocol that doesn't suffer from this is TELNET that
does all authentication and encryption in-bound.
.ti 0 .ti 0
Scenarios Scenarios
@@ -190,9 +186,12 @@ addition to those mentioned in [RFC1510].
.ti 0 .ti 0
References References
[RFC959] Postel, J. and Reynolds, J., \*QFILE TRANSFER PROTOCOL [RFC959] Postel, J. and Reynolds, J., \*QFile Transfer Protocol
(FTP)\*U, RFC 969, October 1985 (FTP)\*U, RFC 969, October 1985
[RFC1416] Borman, D., \*QTelnet Authentication Option\*U, RFC 1416,
February 1993.
[RFC1510] Kohl, J. and Neuman, C., \*QThe Kerberos Network [RFC1510] Kohl, J. and Neuman, C., \*QThe Kerberos Network
Authentication Service (V5)\*U, RFC 1510, September 1993. Authentication Service (V5)\*U, RFC 1510, September 1993.

View File

@@ -61,8 +61,8 @@ Abstract
.ti 0 .ti 0
Introduction Introduction
Kerberos is a protocol for authenticating parties communicating over Kerberos[RFC1510] is a protocol for authenticating parties
insecure networks. communicating over insecure networks.
Firewalling is a technique for achieving an illusion of security by Firewalling is a technique for achieving an illusion of security by
putting restrictions on what kinds of packets and how these are sent putting restrictions on what kinds of packets and how these are sent
@@ -72,8 +72,6 @@ between the internal (so called \*Qsecure\*U) network and the global (or
.ti 0 .ti 0
Definitions Definitions
types of firewalls: ...
client: the user, process, and host acquiring tickets from the KDC and client: the user, process, and host acquiring tickets from the KDC and
authenticating itself to the kerberised server. authenticating itself to the kerberised server.
@@ -86,16 +84,16 @@ client, for example telnetd.
Firewalls Firewalls
A firewall is usually placed between the \*Qinside\*U and the A firewall is usually placed between the \*Qinside\*U and the
\*Qoutside\*U and is supposed to protect the inside from the evils on \*Qoutside\*U networks, and is supposed to protect the inside from the
the outside. There are different kinds of firewalls. The main evils on the outside. There are different kinds of firewalls. The
differences are in the way they forward packets. main differences are in the way they forward packets.
.Ip 1 .Ip \(bu
The most straight forward type is the one that just imposes The most straight forward type is the one that just imposes
restrictions on incoming packets. Such a firewall could be described restrictions on incoming packets. Such a firewall could be described
as a router that just throws away packets that match some criteria. as a router that filters packets that match some criteria.
.Ip 2 .Ip \(bu
They may also \*Qhide\*U some or all addresses on the inside of the They may also \*Qhide\*U some or all addresses on the inside of the
firewall, replacing the addresses in the outgoing packets with the firewall, replacing the addresses in the outgoing packets with the
address of the firewall (aka network address translation, or NAT). NAT address of the firewall (aka network address translation, or NAT). NAT
@@ -108,7 +106,7 @@ There are also firewalls that does NAT both on the inside and the
outside (a server on the inside will see this as a connection from the outside (a server on the inside will see this as a connection from the
firewall). firewall).
.Ip 3 .Ip \(bu
A third type is the proxy type firewall, that parses the contents of A third type is the proxy type firewall, that parses the contents of
the packets, basically acting as a server to the client, and as a the packets, basically acting as a server to the client, and as a
client to the server (man-in-the-middle). If Kerberos is to be used client to the server (man-in-the-middle). If Kerberos is to be used
@@ -116,19 +114,17 @@ with this kind of firewall, a protocol module that handles KDC
requests has to be written. requests has to be written.
.in 3 .in 3
This type of firewall might also add extra trouble when used with This type of firewall might also cause extra trouble when used with
kerberised versions of protocols that the proxy understands, in kerberised versions of protocols that the proxy understands, in
addition to the ones mentioned below. addition to the ones mentioned below. This is the case with the FTP
Security Extensions [RFC2228], that adds a new set of commands to the
This is the case with the FTP Security Extensions [RFC2228], that adds FTP protocol [RFC959], for integrity, confidentiality, and privacy
a new set of commands to the FTP protocol [RFC959], for integrity, protecting commands. When transferring data, the FTP protocol uses a
confidentiality, and privacy protecting commands. When transferring separate data channel, and an FTP proxy will have to look out for
data, the FTP protocol uses a separate data channel, and an FTP proxy commands that start a data transfer. If all commands are encrypted,
will have to look out for commands that start a data transfer. If all this is impossible. A protocol that doesn't suffer from this is the
commands are encrypted, this is impossible. Telnet Authentication Option [RFC1416] that does all authentication
and encryption in-bound.
An example of a protocol that doesn't suffer from this is TELNET that
does all authentication and encryption in-bound.
.ti 0 .ti 0
Scenarios Scenarios
@@ -190,9 +186,12 @@ addition to those mentioned in [RFC1510].
.ti 0 .ti 0
References References
[RFC959] Postel, J. and Reynolds, J., \*QFILE TRANSFER PROTOCOL [RFC959] Postel, J. and Reynolds, J., \*QFile Transfer Protocol
(FTP)\*U, RFC 969, October 1985 (FTP)\*U, RFC 969, October 1985
[RFC1416] Borman, D., \*QTelnet Authentication Option\*U, RFC 1416,
February 1993.
[RFC1510] Kohl, J. and Neuman, C., \*QThe Kerberos Network [RFC1510] Kohl, J. and Neuman, C., \*QThe Kerberos Network
Authentication Service (V5)\*U, RFC 1510, September 1993. Authentication Service (V5)\*U, RFC 1510, September 1993.