What is a dialup interface


A dialup interface is the interface where a call has been established. A dialup interface can be a dialer interface, a physical interface bound to the dialer interface, or a physical interface carrying DCC parameters.

Other related questions:
Why does dialup often fail on a 3G cellular interface

The possible causes are as follows:

  • The 3G data card cannot be identified on the current network or is not supported on the AR.
  • The 3G data card does not match the current network. For example, authentication or service required on the current network is not enabled on the data card or USIM/SIM card. As a result, authentication or negotiation fails in dialup.
  • The 3G data card is not registered with available networks, due to weak signal strength or other reasons. Run the display cellular command to check information about 3G signals. The Current Service Status field must be displayed as "Service available", and the signal strength must be in the allowed range.
  • An incorrect connection mode is configured on the 3G data card. For example, the 3G data card has a SIM card installed but its connection mode is set to WCDMA-only.
  • The USIM/SIM card is not properly installed.
  • The 2G/3G services are not enabled on the USIM/SIM card.
  • The account balance of the USIM/SIM card is insufficient.
  • The USIM/SIM card works incorrectly. Run the display cellular command to check whether the USIM/SIM card is in correct state. The status of the USIM/SIM card must be Ok not Not insert.
  • Check whether 3G configurations, including the dialer number are correct. Check whether PPP authentication is required when the 3G cellular interface accesses a CDMA2000 network.
  • No profile is configured or a profile is incorrectly configured.
  • The 3G cellular interface is shut down using the shutdown command.

How is the NAT server configured on the PPPoE dialup interface
On an AR, the NAT server can be configured on the PPPoE dialup interface. 1. Create a dialup interface and configure parameters on the dialup interface. 2. Configure the NAT server on the dialup interface. The internal IP address of the internal server is, the port used for providing services is port 8080, and the external address is [Huawei] interface dialer 1 [Huawei-Dialer1] nat server protocol tcp global www inside 8080 [Huawei-Dialer1] quit

What are the causes of the L2TP dialup failure
The causes of the L2TP dialup failure are as follows: -The firewall deployed on the public network or the built-in firewall on the PC discards L2TP packets. -The corresponding L2TP port, usually UDP port 1701, is disabled or occupied. For example: ACL or NAT is configured on the port. -The user name and password configured on the LAC are incorrect, or no related user is configured on the LNS. -The configuration address, such as the static address of the VT interface, is incorrect. -The tunnel authentication modes are different. -LCP renegotiation is not configured. -The address pool cannot meet user requirement or no address pool is configured. -No gateway address is reserved in the IP address pool, so that the gateway address is allocated to users. -The LAC and LNS have no reachable routes to each other. -An incorrect remote tunnel name is specified in the L2TP group view. -The authentication domain is incorrectly configured. -The control packets sent by the PC client do not carry the SQ number, so that the L2TP negotiation fails. -When IPSec encryption is used, the IPSec parameters on both ends are different.

Which interfaces of the AR router support PPPoE dialup
1. A VT interface must be bound to an interface so that the PPPoE server can be implemented. The PPPoE server can be configured on a physical Ethernet interface, a PON interface, a VLANIF interface, or a virtual Ethernet interface. 2. The dialer interface must be bound to an interface so that the PPPoE client can be implemented. The PPPoE client can be configured on a physical Ethernet interface, a PON interface, or a virtual Ethernet interface. The physical Ethernet interfaces refer to WAN-side Ethernet interfaces. LAN-side Ethernet interfaces do not support PPPoE.

The PPPoE physical interface is Up but the state of the protocol is Down
After a PPPoE dialup, all services are born on the Dialer interface, with corresponding physical interface being Up and protocol being Down, which is normal and does not affect the services and use. Ignore it. A virtual interface is needed for PPPoE dialup to bear all services. Pay attention to the Dialer interface, and the protocol status does not need to be concerned with.

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