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IPsec VPN Overview

A VPN is a private network that uses a public network to connect two or more remote sites. Instead of using dedicated connections between networks, VPNs use virtual connections routed (tunneled) through public networks. IPsec VPN is a protocol, consists of set of standards used to establish a VPN connection.

IPsec VPN Overview

A VPN provides a means by which remote computers communicate securely across a public WAN such as the Internet.

A VPN connection can link two LANs (site-to-site VPN) or a remote dial-up user and a LAN. The traffic that flows between these two points passes through shared resources such as routers, switches, and other network equipment that make up the public WAN. To secure VPN communication while passing through the WAN, the two participants create an IP Security (IPsec) tunnel.

The term tunnel does not denote tunnel mode (see Packet Processing in Tunnel Mode). Instead, it refers to the IPsec connection.

IPsec is a suite of related protocols for cryptographically securing communications at the IP Packet Layer. IPsec also provides methods for the manual and automatic negotiation of security associations (SAs) and key distribution, all the attributes for which are gathered in a domain of interpretation (DOI). The IPsec DOI is a document containing definitions for all the security parameters required for the successful negotiation of a VPN tunnel—essentially, all the attributes required for SA and IKE negotiations. See RFC 2407 and RFC 2408 for more information.

This topic includes the following sections:

Security Associations

A security association (SA) is a unidirectional agreement between the VPN participants regarding the methods and parameters to use in securing a communication channel. Full bidirectional communication requires at least two SAs, one for each direction. Through the SA, an IPsec tunnel can provide the following security functions:

  • Privacy (through encryption)

  • Content integrity (through data authentication)

  • Sender authentication and—if using certificates—nonrepudiation (through data origin authentication)

The security functions you employ depend on your needs. If you need only to authenticate the IP packet source and content integrity, you can authenticate the packet without applying any encryption. On the other hand, if you are concerned only with preserving privacy, you can encrypt the packet without applying any authentication mechanisms. Optionally, you can both encrypt and authenticate the packet. Most network security designers choose to encrypt, authenticate, and replay-protect their VPN traffic.

An IPsec tunnel consists of a pair of unidirectional SAs—one SA for each direction of the tunnel—that specify the security parameter index (SPI), destination IP address, and security protocol (Authentication Header [AH] or Encapsulating Security Payload [ESP] employed. An SA groups together the following components for securing communications:

For inbound traffic, Junos OS looks up the SA by using the following triplet:

  • Destination IP address.

  • Security protocol, either AH or ESP. (See IPsec Security Protocols.)

  • Security parameter index (SPI) value.

For outbound VPN traffic, the policy invokes the SA associated with the VPN tunnel.

IPsec Key Management

The distribution and management of keys are critical to using VPNs successfully. Junos OS supports IPsec technology for creating VPN tunnels with three kinds of key creation mechanisms:

  • Manual key

  • AutoKey IKE with a preshared key or a certificate

You can choose your key creation mechanism—also called authentication method—during Phase 1 and Phase 2 proposal configuration. See IPsec Tunnel Negotiation.

This topic includes the following sections:

Manual Key

With manual keys, administrators at both ends of a tunnel configure all the security parameters. This is a viable technique for small, static networks where the distribution, maintenance, and tracking of keys are not difficult. However, safely distributing manual-key configurations across great distances poses security issues. Aside from passing the keys face-to-face, you cannot be completely sure that the keys have not been compromised while in transit. Also, whenever you want to change the key, you are faced with the same security issues as when you initially distributed it.

AutoKey IKE

When you need to create and manage numerous tunnels, you need a method that does not require you to configure every element manually. IPsec supports the automated generation and negotiation of keys and security associations using the Internet Key Exchange (IKE) protocol. Junos OS refers to such automated tunnel negotiation as AutoKey IKE and supports AutoKey IKE with preshared keys and AutoKey IKE with certificates.

  • AutoKey IKE with preshared keys—Using AutoKey IKE with preshared keys to authenticate the participants in an IKE session, each side must configure and securely exchange the preshared key in advance. In this regard, the issue of secure key distribution is the same as that with manual keys. However, once distributed, an autokey, unlike a manual key, can automatically change its keys at predetermined intervals using the IKE protocol. Frequently changing keys greatly improves security, and automatically doing so greatly reduces key-management responsibilities. However, changing keys increases traffic overhead; therefore, changing keys too often can reduce data transmission efficiency.

    A preshared key is a key for both encryption and decryption, which both participants must have before initiating communication.

  • AutoKey IKE with certificates—When using certificates to authenticate the participants during an AutoKey IKE negotiation, each side generates a public-private key pair and acquires a certificate. As long as the issuing certificate authority (CA) is trusted by both sides, the participants can retrieve the peer’s public key and verify the peer's signature. There is no need to keep track of the keys and SAs; IKE does it automatically.

Diffie-Hellman Exchange

A Diffie-Hellman (DH) exchange allows participants to produce a shared secret value. The strength of the technique is that it allows participants to create the secret value over an unsecured medium without passing the secret value through the wire. The size of the prime modulus used in each group's calculation differs as shown in the below table. Diffie Hellman (DH) exchange operations can be performed either in software or in hardware. When these exchange operations are performed in hardware, we utilize QuickAssist Technology (QAT) cryptography. The following Table 1 lists different Diffie Hellman (DH) groups and specifies whether the operation performed for that group is in the hardware or in software.

Table 1: Diffie Hellman (DH) groups and their exchange operations performed

Diffie-Hellman (DH) Group

Prime Module Size

Exchange Operation Performed at

DH Group 1

768-bit

Hardware

DH Group 2

102-bit

Hardware

DH Group 5

1536-bit

Hardware

DH Group 14

2048-bit

Hardware

DH Group 15

3072-bit

Software

DH Group 16

4096-bit

Software

DH Group 19

256-bit elliptic curve

Software

DH Group 20

384-bit elliptic curve

Software

DH Group 21

521-bit elliptic curve

Software

DH Group 24

2048-bit with 256-bit prime order subgroup

Software

Starting in Junos OS Release 19.1R1, SRX Series devices support DH groups 15, 16, and 21.

We do not recommend the use of DH groups 1, 2, and 5.

Because the modulus for each DH group is a different size, the participants must agree to use the same group.

IPsec Security Protocols

IPsec uses two protocols to secure communications at the IP layer:

  • Authentication Header (AH)—A security protocol for authenticating the source of an IP packet and verifying the integrity of its content

  • Encapsulating Security Payload (ESP)—A security protocol for encrypting the entire IP packet (and authenticating its content)

You can choose your security protocols—also called authentication and encryption algorithms—during Phase 2 proposal configuration. See IPsec Tunnel Negotiation.

For each VPN tunnel, both AH and ESP tunnel sessions are installed on Services Processing Units (SPUs) and the control plane. Tunnel sessions are updated with the negotiated protocol after negotiation is completed. For SRX5400, SRX5600, and SRX5800 devices, tunnel sessions on anchor SPUs are updated with the negotiated protocol while non-anchor SPUs retain ESP and AH tunnel sessions. ESP and AH tunnel sessions are displayed in the outputs for the show security flow session and show security flow cp-session operational mode commands.

This topic includes the following sections:

AH Protocol

The Authentication Header (AH) protocol provides a means to verify the authenticity and integrity of the content and origin of a packet. You can authenticate the packet by the checksum calculated through a Hash Message Authentication Code (HMAC) using a secret key and either MD5 or SHA hash functions.

  • Message Digest 5 (MD5)—An algorithm that produces a 128-bit hash (also called a digital signature or message digest) from a message of arbitrary length and a 16-byte key. The resulting hash is used, like a fingerprint of the input, to verify content and source authenticity and integrity.

  • Secure Hash Algorithm (SHA)—An algorithm that produces a 160-bit hash from a message of arbitrary length and a 20-byte key. It is generally regarded as more secure than MD5 because of the larger hashes it produces. Because the computational processing is done in the ASIC, the performance cost is negligible.

For more information on MD5 hashing algorithms, see RFC 1321 and RFC 2403. For more information on SHA hashing algorithms, see RFC 2404. For more information on HMAC, see RFC 2104.

ESP Protocol

The Encapsulating Security Payload (ESP) protocol provides a means to ensure privacy (encryption) and source authentication and content integrity (authentication). ESP in tunnel mode encapsulates the entire IP packet (header and payload) and then appends a new IP header to the now-encrypted packet. This new IP header contains the destination address needed to route the protected data through the network. (See Packet Processing in Tunnel Mode.)

With ESP, you can both encrypt and authenticate, encrypt only, or authenticate only. For encryption, you can choose one of the following encryption algorithms:

  • Data Encryption Standard (DES)—A cryptographic block algorithm with a 56-bit key.

  • Triple DES (3DES)—A more powerful version of DES in which the original DES algorithm is applied in three rounds, using a 168-bit key. DES provides significant performance savings but is considered unacceptable for many classified or sensitive material transfers.

  • Advanced Encryption Standard (AES)—An encryption standard which offers greater interoperability with other devices. Junos OS supports AES with 128-bit, 192-bit, and 256-bit keys.

For authentication, you can use either MD5 or SHA algorithms.

Even though it is possible to select NULL for encryption, it has been demonstrated that IPsec might be vulnerable to attack under such circumstances. Therefore, we suggest that you choose an encryption algorithm for maximum security.

IPsec Tunnel Negotiation

To establish an AutoKey IKE IPsec tunnel, two phases of negotiation are required:

  • In Phase 1, the participants establish a secure channel in which to negotiate the IPsec security associations (SAs).

  • In Phase 2, the participants negotiate the IPsec SAs for encrypting and authenticating the ensuing exchanges of user data.

For a manual key IPsec tunnel, because all the SA parameters have been previously defined, there is no need to negotiate which SAs to use. In essence, the tunnel has already been established. When traffic matches a policy using that manual key tunnel or when a route involves the tunnel, the Juniper Networks device simply encrypts and authenticates the data, as you determined, and forwards it to the destination gateway.

The remote IKE gateway address can be in any virtual routing (VR) instance. VR is determined during IKE Phase 1 and Phase 2 negotiation. VR does not have to be configured in the IKE proposals. If the IKE gateway interface is moved from one VR to another, the existing IKE Phase 1 and Phase 2 negotiations for the IKE gateway are cleared, and new Phase 1 and Phase 2 negotiations are performed.

  • On SRX Series devices, when you enable VPN, overlapping of IP addresses across virtual routers is supported with the following limitations:

    • An IKE external interface address cannot overlap with any other virtual router.

    • An internal or trust interface address can overlap across virtual routers.

    • An st0 interface address cannot overlap in route-based VPN in point-to-multipoint tunnel such as NHTB.

    • An st0 interface address can overlap in route-based VPN in point-to-point tunnel.

  • The combinations of local IP addresses and remote gateway IP addresses of IPsec VPN tunnels configured across VRs have to be unique.

  • When the loopback interface is used as the IKE gateway external interface, the physical interface for IKE negotiation should be in the same VR.

IPsec VPN Topologies on SRX Series Devices

The following are some of the IPsec VPN topologies that Junos operating system (OS) supports:

  • Site-to-site VPNs—Connects two sites in an organization together and allows secure communications between the sites.

  • Hub-and-spoke VPNs—Connects branch offices to the corporate office in an enterprise network. You can also use this topology to connect spokes together by sending traffic through the hub.

  • Remote access VPNs—Allows users working at home or traveling to connect to the corporate office and its resources. This topology is sometimes referred to as an end-to-site tunnel.

Comparing Policy-Based and Route-Based VPNs

It is important to understand the differences between policy-based and route-based VPNs and why one might be preferable to the other.

Table 2 lists the differences between route-based VPNs and policy-based VPNs.

Table 2: Differences Between Route-Based VPNs and Policy-Based VPNs

Route-Based VPNs

Policy-Based VPNs

With route-based VPNs, a policy does not specifically reference a VPN tunnel.

With policy-based VPN tunnels, a tunnel is treated as an object that, together with source, destination, application, and action, constitutes a tunnel policy that permits VPN traffic.

The policy references a destination address.

In a policy-based VPN configuration, a tunnel policy specifically references a VPN tunnel by name.

The number of route-based VPN tunnels that you create is limited by the number of route entries or the number of st0 interfaces that the device supports, whichever number is lower.

The number of policy-based VPN tunnels that you can create is limited by the number of policies that the device supports.

Route-based VPN tunnel configuration is a good choice when you want to conserve tunnel resources while setting granular restrictions on VPN traffic.

With a policy-based VPN, although you can create numerous tunnel policies referencing the same VPN tunnel, each tunnel policy pair creates an individual IPsec security association (SA) with the remote peer. Each SA counts as an individual VPN tunnel.

With a route-based approach to VPNs, the regulation of traffic is not coupled to the means of its delivery. You can configure dozens of policies to regulate traffic flowing through a single VPN tunnel between two sites, and only one IPsec SA is at work. Also, a route-based VPN configuration allows you to create policies referencing a destination reached through a VPN tunnel in which the action is deny.

In a policy-based VPN configuration, the action must be permit and must include a tunnel.

Route-based VPNs support the exchange of dynamic routing information through VPN tunnels. You can enable an instance of a dynamic routing protocol, such as OSPF, on an st0 interface that is bound to a VPN tunnel.

The exchange of dynamic routing information is not supported in policy-based VPNs.

Route-based configurations are used for hub-and-spoke topologies.

Policy-based VPNs cannot be used for hub-and-spoke topologies.

With route-based VPNs, a policy does not specifically reference a VPN tunnel.

When a tunnel does not connect large networks running dynamic routing protocols and you do not need to conserve tunnels or define various policies to filter traffic through the tunnel, a policy-based tunnel is the best choice.

Route-based VPNs do not support remote-access (dial-up) VPN configurations.

Policy-based VPN tunnels are required for remote-access (dial-up) VPN configurations.

Route-based VPNs might not work correctly with some third-party vendors.

Policy-based VPNs might be required if the third party requires separate SAs for each remote subnet.

When the security device does a route lookup to find the interface through which it must send traffic to reach an address, it finds a route via a secure tunnel interface (st0) , which is bound to a specific VPN tunnel.

With a route-based VPN tunnel, you can consider a tunnel as a means for delivering traffic, and can consider the policy as a method for either permitting or denying the delivery of that traffic.

With a policy-based VPN tunnel, you can consider a tunnel as an element in the construction of a policy.

Route-based VPNs support NAT for st0 interfaces.

Policy-based VPNs cannot be used if NAT is required for tunneled traffic.

Proxy ID is supported for both route-based and policy-based VPNs. Route-based tunnels also offer the usage of multiple traffic selectors also known as multi-proxy ID. A traffic selector is an agreement between IKE peers to permit traffic through a tunnel, if the traffic matches a specified pair of local and remote IP address prefix, source port range, destination port range, and protocol. You define a traffic selector within a specific route-based VPN, which can result in multiple Phase 2 IPsec SAs. Only traffic that conforms to a traffic selector is permitted through an SA. The traffic selector is commonly required when remote gateway devices are non-Juniper Networks devices.

Policy-based VPNs are only supported on SRX5400, SRX5600, and SRX5800 devices. Platform support depends on the Junos OS release in your installation.

Comparison of Policy-Based VPNs and Route-Based VPNs

Table 3 summarizes the differences between policy-based VPNs and route-based VPNs.

Table 3: Comparison Between Policy-Based VPNs and Route-Based VPNs

Policy-Based VPNs

Route-Based VPNs

In policy-based VPNs, a tunnel is treated as an object that, together with source, destination, application, and action, constitutes a tunnel policy that permits VPN traffic.

In route-based VPNs, a policy does not specifically reference a VPN tunnel.

A tunnel policy specifically references a VPN tunnel by name.

A route determines which traffic is sent through the tunnel based on a destination IP address.

The number of policy-based VPN tunnels that you can create is limited by the number of tunnels that the device supports.

The number of route-based VPN tunnels that you create is limited by the number of st0 interfaces (for point-to-point VPNs) or the number of tunnels that the device supports, whichever is lower.

With a policy-based VPN, although you can create numerous tunnel policies referencing the same VPN tunnel, each tunnel policy pair creates an individual IPsec SA with the remote peer. Each SA counts as an individual VPN tunnel.

Because the route, not the policy, determines which traffic goes through the tunnel, multiple policies can be supported with a single SA or VPN.

In a policy-based VPN, the action must be permit and must include a tunnel.

In a route-based VPN, the regulation of traffic is not coupled to the means of its delivery.

The exchange of dynamic routing information is not supported in policy-based VPNs.

Route-based VPNs support the exchange of dynamic routing information through VPN tunnels. You can enable an instance of a dynamic routing protocol, such as OSPF, on an st0 interface that is bound to a VPN tunnel.

If you need more granularity than a route can provide to specify the traffic sent to a tunnel, using a policy-based VPN with security policies is the best choice.

Route-based VPNs uses routes to specify the traffic sent to a tunnel; a policy does not specifically reference a VPN tunnel.

With a policy-based VPN tunnel, you can consider a tunnel as an element in the construction of a policy.

When the security device does a route lookup to find the interface through which it must send traffic to reach an address, it finds a route through a secure tunnel (st0) interface.

With a route-based VPN tunnel, you can consider a tunnel as a means for delivering traffic, and can consider the policy as a method for either permitting or denying the delivery of that traffic.

Understanding IKE and IPsec Packet Processing

An IPsec VPN tunnel consists of tunnel setup and applied security. During tunnel setup, the peers establish security associations (SAs), which define the parameters for securing traffic between themselves. (See IPsec VPN Overview.) After the tunnel is established, IPsec protects the traffic sent between the two tunnel endpoints by applying the security parameters defined by the SAs during tunnel setup. Within the Junos OS implementation, IPsec is applied in tunnel mode, which supports the Encapsulating Security Payload (ESP) and Authentication Header (AH) protocols.

This topic includes the following sections:

Packet Processing in Tunnel Mode

IPsec operates in one of two modes—transport or tunnel. When both ends of the tunnel are hosts, you can use either mode. When at least one of the endpoints of a tunnel is a security gateway, such as a Junos OS router or firewall, you must use tunnel mode. Juniper Networks devices always operate in tunnel mode for IPsec tunnels.

In tunnel mode, the entire original IP packet—payload and header—is encapsulated within another IP payload, and a new header is appended to it, as shown in Figure 1. The entire original packet can be encrypted, authenticated, or both. With the Authentication Header (AH) protocol, the AH and new headers are also authenticated. With the Encapsulating Security Payload (ESP) protocol, the ESP header can also be authenticated.

Figure 1: Tunnel ModeTunnel Mode

In a site-to-site VPN, the source and destination addresses used in the new header are the IP addresses of the outgoing interface. See Figure 2.

Figure 2: Site-to-Site VPN in Tunnel ModeSite-to-Site VPN in Tunnel Mode

In a dial-up VPN, there is no tunnel gateway on the VPN dial-up client end of the tunnel; the tunnel extends directly to the client itself (see Figure 3). In this case, on packets sent from the dial-up client, both the new header and the encapsulated original header have the same IP address: that of the client’s computer.

Some VPN clients, such as the dynamic VPN client and Netscreen-Remote, use a virtual inner IP address (also called a “sticky address”). Netscreen-Remote enables you to define the virtual IP address. The dynamic VPN client uses the virtual IP address assigned during the XAuth configuration exchange. In such cases, the virtual inner IP address is the source IP address in the original packet header of traffic originating from the client, and the IP address that the ISP dynamically assigns the dial-up client is the source IP address in the outer header.

Figure 3: Dial-Up VPN in Tunnel ModeDial-Up VPN in Tunnel Mode

Distribution of IKE and IPsec Sessions Across SPUs

In the SRX5400, SRX5600, and SRX5800 devices, IKE provides tunnel management for IPsec and authenticates end entities. IKE performs a Diffie-Hellman (DH) key exchange to generate an IPsec tunnel between network devices. The IPsec tunnels generated by IKE are used to encrypt, decrypt, and authenticate user traffic between the network devices at the IP layer.

The VPN is created by distributing the IKE and IPsec workload among the multiple Services Processing Units (SPUs) of the platform. For site-to-site tunnels, the least-loaded SPU is chosen as the anchor SPU. If multiple SPUs have the same smallest load, any of them can be chosen as an anchor SPU. Here, load corresponds to the number of site-to-site gateways or manual VPN tunnels anchored on an SPU. For dynamic tunnels, the newly established dynamic tunnels employ a round-robin algorithm to select the SPU.

In IPsec, the workload is distributed by the same algorithm that distributes the IKE. The Phase 2 SA for a given VPN tunnel termination points pair is exclusively owned by a particular SPU, and all IPsec packets belonging to this Phase 2 SA are forwarded to the anchoring SPU of that SA for IPsec processing.

Multiple IPsec sessions (Phase 2 SA) can operate over one or more IKE sessions. The SPU that is selected for anchoring the IPsec session is based on the SPU that is anchoring the underlying IKE session. Therefore, all IPsec sessions that run over a single IKE gateway are serviced by the same SPU and are not load-balanced across several SPUs.

Table 4 shows an example of an SRX5000 line device with three SPUs running seven IPsec tunnels over three IKE gateways.

Table 4: Distribution of IKE and IPsec Sessions Across SPUs

SPU

IKE Gateway

IPsec Tunnel

SPU0

IKE-1

IPsec-1

IPsec-2

IPsec-3

SPU1

IKE-2

IPsec-4

IPsec-5

IPsec-6

SPU2

IKE-3

IPsec-7

The three SPUs have an equal load of one IKE gateway each. If a new IKE gateway is created, SPU0, SPU1, or SPU2 could be selected to anchor the IKE gateway and its IPsec sessions.

Setting up and tearing down existing IPsec tunnels does not affect the underlying IKE session or existing IPsec tunnels.

Use the following show command to view the current tunnel count per SPU: show security ike tunnel-map.

Use the summary option of the command to view the anchor points of each gateway: show security ike tunnel-map summary.

VPN Support for Inserting Services Processing Cards

SRX5400, SRX5600, and SRX5800 devices have a chassis-based distributed processor architecture. The flow processing power is shared and is based on the number of Services Processing Cards (SPCs). You can scale the processing power of the device by installing new SPCs.

In an SRX5400, SRX5600, or SRX5800 chassis cluster, you can insert new SPCs on the devices without affecting or disrupting the traffic on the existing IKE or IPsec VPN tunnels. When you insert a new SPC in each chassis of the cluster, the existing tunnels are not affected and traffic continues to flow without disruption.

Starting in Junos OS Release 19.4R1, on all SRX5000 Series devices chassis cluster, you can insert a new SRX5K-SPC3 (SPC3) or SRX5K-SPC-4-15-320 (SPC2) card to an existing chassis containing SPC3 card. You can only insert the cards in a higher slot than the existing SPC3 card on the chassis. You must reboot the node after the inserting SPC3 to activate the card. After the node reboot is complete, IPsec tunnels are distributed to the cards.

However, existing tunnels cannot use the processing power of the Service Processing Units (SPUs) in the new SPCs. A new SPU can anchor newly established site-to-site and dynamic tunnels. Newly configured tunnels are not, however, guaranteed to be anchored on a new SPU.

Site-to-site tunnels are anchored on different SPUs based on a load-balancing algorithm. The load-balancing algorithm is dependent on number flow threads each SPU is using. Tunnels belonging to the same local and remote gateway IP addresses are anchored on the same SPU on different flow RT threads used by the SPU. The SPU with the smallest load is chosen as the anchor SPU. Each SPU maintains number of flow RT threads that are hosted in that particular SPU. The number of flow RT threads hosted on each SPU vary based on the type of SPU.

Tunnel load factor = Number of tunnels anchored on the SPU / Total number of flow RT threads used by the SPU.

Dynamic tunnels are anchored on different SPUs based on a round-robin algorithm. Newly configured dynamic tunnels are not guaranteed to be anchored on the new SPC.

Starting in Junos OS Release 18.2R2 and 18.4R1, all the existing IPsec VPN features that are currently supported on SRX5K-SPC3 (SPC3) only will be supported on SRX5400, SRX5600, and SRX5800 devices when SRX5K-SPC-4-15-320 (SPC2) and SPC3 cards are installed and operating on the device in a chassis cluster mode or in a standalone mode.

When both SPC2 and SPC3 cards are installed, you can verify the tunnel mapping on different SPUs using the show security ipsec tunnel-distribution command.

Use the command show security ike tunnel-map to view the tunnel mapping on different SPUs with only SPC2 card inserted. The command show security ike tunnel-map is not valid in an environment where SPC2 and SPC3 cards are installed.

Inserting SPC3 Card: Guidelines and Limitations:

  • In a chassis cluster, if one of the nodes has 1 SPC3 card and the other node has 2 SPC3 cards, the failover to the node that has 1 SPC3 card is not supported.

  • You must insert the SPC3 or SPC2 in an existing chassis in a higher slot than a current SPC3 present in a lower slot.

  • For SPC3 ISHU to work, you must insert the new SPC3 card into the higher slot number.

  • On SRX5800 chassis cluster, you must not insert the SPC3 card in the highest slot (slot no. 11) due to the power and heat distribution limit.

  • We do not support SPC3 hot removal.

Enabling IPsec VPN Feature Set on SRX5K-SPC3 Services Processing Card

SRX5000 line of devices with SRX5K-SPC3 card requires junos-ike package to install and to enable any of the IPsec VPN features. By default, junos-ike package is installed in Junos OS Releases 20.1R2, 20.2R2, 20.3R2, 20.4R1, and later for SRX5000 line of devices with RE3. As a result iked and ikemd process runs on the routing engine by default instead of IPsec key management daemon (kmd).

If you want to use KMD process to enable the IPsec VPN feature instead of default IKE, run request system software delete junos-ike command.

To check the installed junos-ike package, use the following command:

IPsec VPN Feature Support on SRX5000 Line of Devices with SRX5K-SPC3 and vSRX Instances with New Package

This topic provides you a summary of IPsec VPN features and configurations that are not supported of SRX5000 line of devices with SPC3 and on vSRX instances.

IPsec VPN feature is supported by two processes, iked and ikemd on SRX5K-SPC3 and vSRX instances. A single instance of iked and ikemd will run on the Routing Engine at a time.

By default, Junos-ike package is installed in Junos OS Releases 20.1R2, 20.2R2, 20.3R2, 20.4R1, and later for SRX5000 line of devices with RE3, and both the iked and ikemd process runs on the routing engine.

To restart ikemd process in the Routine Engine use the restart ike-config-management command.

To restart iked process in the Routing Engine use the restart ike-key-management command.

If you want to use KMD process to enable the IPsec VPN feature instead of default IKE, run request system software delete junos-ike command.

IPsec VPN Features Not Supported

To determine if a feature is supported by a specific platform or Junos OS release, refer Feature Explorer.

Table 5: IPsec VPN Feature Support on SRX Series Devices and vSRX Instances

Features

Support on SRX 5000 line of devices with SRX5K-SPC3 and vSRX Instances

Auto Discovery VPN (ADVPN).

No

AutoVPN Protocol Independent Multicast (PIM) point-to-multipoint mode.

No

AutoVPN RIP support for unicast traffic.

No

Bidirectional Forwarding Detection (BFD) over OSPFv3 routes on st0 interface.

Not supported on vSRX

Configuring forwarding class on IPsec VPNs.

No

Config Mode (draft-dukes-ike-mode-cfg-03).

No

Dead peer detection (DPD) and DPD gateway failover.

DPD gateway failover is not supported on vSRX.

AH transport modes.

No

Group VPN.

No

Idle timers for IKE.

No

Idle timers for IPsec SA.

No

Invalid SPI response.

No

Lifetime of IKE SA, in kilobytes.

No

Logical system.

No

Manual VPN.

No

Multicast traffic.

No

Neighbor Discovery Protocol (NDP) over st0 interfaces.

No

Packet size configuration for IPsec datapath verification.

No

Packet reordering for IPv6 fragments over tunnel.

No

Point-to-multipoint tunnel interfaces.

No

Policy-based IPsec VPN.

No

Remote Access.

No

RIP over IPsec.

No

Support group IKE IDs for Dynamic VPN configuration.

Supported on SRX

TOS/DSCP Honoring for IPsec (outer/Inner).

Supported on SRX

Unicast static and dynamic (RIP, OSPF, BGP) routing.

Supported on SRX

VPN monitoring.

No

XAuth

No

Understanding Hub-and-Spoke VPNs

If you create two VPN tunnels that terminate at a device, you can set up a pair of routes so that the device directs traffic exiting one tunnel to the other tunnel. You also need to create a policy to permit the traffic to pass from one tunnel to the other. Such an arrangement is known as hub-and-spoke VPN. (See Figure 4.)

You can also configure multiple VPNs and route traffic between any two tunnels.

SRX Series devices support only the route-based hub-and-spoke feature.

Figure 4: Multiple Tunnels in a Hub-and-Spoke VPN ConfigurationMultiple Tunnels in a Hub-and-Spoke VPN Configuration
Release History Table
Release
Description
20.1R2
By default, junos-ike package is installed in Junos OS Releases 20.1R2, 20.2R2, 20.3R2, 20.4R1, and later for SRX5000 line of devices with RE3. As a result iked and ikemd process runs on the routing engine by default instead of IPsec key management daemon (kmd).
19.1R1
Starting in Junos OS Release 19.1R1, SRX Series devices support DH groups 15, 16, and 21.