Руководство Пользователя для Netopia 4741 2a4na
11-12 Administration Guide
Interoperation with other features
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Address ser ving is not suppor ted through IPsec Tunnels.
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AH is not suppor ted through an inter face that has NAT applied to it. NAT may be applied to the inner
payload.
payload.
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AH is not suppor ted through an inter face which is either Unnumbered or Numbered with a dynamically
assigned address unless the Local Tunnel Endpoint address is specified in the Advanced IP Profile Options
screen.
assigned address unless the Local Tunnel Endpoint address is specified in the Advanced IP Profile Options
screen.
Encryption Support
Encr yption is a method for altering user data into a form that is unusable by anyone other than the intended
recipient. The recipient must have the means to decr ypt the data to render it usable to them. The encr yption
process protects the data by making it difficult for any third par ty to get at the original data.
recipient. The recipient must have the means to decr ypt the data to render it usable to them. The encr yption
process protects the data by making it difficult for any third par ty to get at the original data.
Netopia PPTP is fully compatible with Microsoft Point-to-Point Encr yption (MPPE) data encr yption for user data
transfer over the PPTP tunnel. Microsoft Windows NT Ser ver provides MPPE encr yption capability only when
Microsoft Challenge Handshake Authentication Protocol (MS-CHAP) is enabled. Netopia complies with this
feature to allow MPPE only when MS-CHAP is negotiated. MS-CHAP and MPPE are user-selectable options in the
PPTP Tunnel Options screen. If either the client or the ser ver side specifies encr yption, then encr yption
becomes mandator y for both.
transfer over the PPTP tunnel. Microsoft Windows NT Ser ver provides MPPE encr yption capability only when
Microsoft Challenge Handshake Authentication Protocol (MS-CHAP) is enabled. Netopia complies with this
feature to allow MPPE only when MS-CHAP is negotiated. MS-CHAP and MPPE are user-selectable options in the
PPTP Tunnel Options screen. If either the client or the ser ver side specifies encr yption, then encr yption
becomes mandator y for both.
Netopia’s ATMP implementation suppor ts Data Encr yption Standard (DES) data encr yption for user data
transfer over the ATMP tunnel between two Netopia routers. The encr yption option, none or DES, is a selectable
option in the ATMP Tunnel Options screen.
transfer over the ATMP tunnel between two Netopia routers. The encr yption option, none or DES, is a selectable
option in the ATMP Tunnel Options screen.
MS-CHAP V2 and 128-bit strong encryption
Notes:
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The Netopia 4741 suppor ts 128-bit (“strong”) encr yption when using PPTP tunnels.
ATMP does not have an option of using 128-bit MPPE. If you are using ATMP between two Netopia routers
you can optionally set 56-bit DES encr yption.
you can optionally set 56-bit DES encr yption.
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When you choose MS-CHAP as the authentication method for a PPTP tunnel, the Netopia router will star t
negotiating MS-CHAPv2. If the router or VPN adapter client you are connecting to does not suppor t
MS-CHAPv2, the Netopia router will fall back to MS-CHAPv1, or, if the router or VPN adapter client you are
connecting to does not suppor t MPPE at all, the PPP session will be dropped. This is done automatically
and transparently.
negotiating MS-CHAPv2. If the router or VPN adapter client you are connecting to does not suppor t
MS-CHAPv2, the Netopia router will fall back to MS-CHAPv1, or, if the router or VPN adapter client you are
connecting to does not suppor t MPPE at all, the PPP session will be dropped. This is done automatically
and transparently.