If you need a large quantity of ISR4321/K9 product - call us through our toll-free number at (800) 675 5044 or request a quote at live chat and our sales manager will contact you shortly.
Looking for assistance? Connect with one of our experts
+1 (800) 675 5044 (Toll-Free)
FREE Shipping. We are accepting NET 30 Days Purchase Orders. Get a decision in seconds, without affecting your credit.

Cisco ISR4321/K9 ISR 4321 2 Ports 4 Slots Security Router Refurbished

Availability: In Stock
Part Number#: ISR4321/K9
List Price was: $565.38
Your Price:
You Save: $418.38 (74% off)

Additional 5% Discount on Checkout

Short Description:
ISR4321/K9 Integrated Service Router (ISR) Series 2 Ports 4 Slots Rack-Mountable Wall Mountable Gigabit Ethernet Security Router | Made by Cisco | Refurbished
Product Condition:
Warranty provided by ALLHDD.COM:
90 Days

Product Overview of the Cisco ISR4321/K9

The Cisco ISR4321/K9 Integrated Service Router, part of the ISR Series, is a powerful and versatile network device designed for a wide range of applications. In this comprehensive guide, we'll delve into its features, capabilities, and benefits, shedding light on why it's a preferred choice for many businesses. The Cisco ISR4321/K9 is a robust integrated service router that combines multiple functions into a single device. With 2 ports and 4 slots, it offers exceptional performance and scalability, making it an ideal solution for businesses of all sizes.

Ports and Slots

  • Gigabit Ethernet Ports: The router is equipped with Gigabit Ethernet ports that provide high-speed connectivity for data transmission. These ports ensure rapid data transfer, facilitating smooth and efficient network operations.
  • Expansion Slots: With 4 expansion slots, the ISR4321/K9 allows for additional modules to be added, offering flexibility and customization to meet specific network requirements.
  • Rack-Mountable and Wall-Mountable The router is designed to be versatile in terms of installation. It can be rack-mounted, which is suitable for data centers and server rooms. Alternatively, it can be wall-mounted, making it ideal for smaller offices or spaces with limited rack infrastructure.
  • Gigabit Ethernet Security The Cisco ISR4321/K9 prioritizes network security, a critical concern in today's digital landscape. It comes equipped with advanced security features to safeguard your data and infrastructure.
  • Firewall Protection: The router provides firewall protection to block unauthorized access and secure your network from external threats.
  • VPN Support: Virtual Private Network (VPN) capabilities ensure secure and encrypted communication between remote sites or users.
  • Intrusion Prevention System (IPS): An integrated IPS adds an extra layer of security by detecting and preventing potential threats in real time.

Versatility and Scalability

  • The ISR4321/K9 is highly adaptable and can be tailored to meet the evolving needs of your network. The availability of expansion slots allows you to add modules like network interface cards (NICs), increasing the router's functionality as your business grows.
  • Quality of Service (QoS) The router supports Quality of Service (QoS) features, which enable you to prioritize specific types of traffic on your network. This ensures that critical applications and services receive the necessary bandwidth and perform optimally.
  • Cisco IOS Software The Cisco ISR4321/K9 runs on Cisco's renowned IOS (Internetwork Operating System) software. This operating system is known for its reliability, security, and robustness. It provides a stable platform for network management and control.
  • Energy Efficiency Cisco has designed the ISR4321/K9 with energy efficiency in mind. It's a green solution that helps reduce power consumption and, in turn, operational costs.

More Information

The Cisco ISR 4321 is a router designed for small and medium-sized businesses, enterprise branch offices, and service provider edge applications. It is equipped with 2 network interface slots and 4 service module slots, which can be used to add a variety of connectivity and service options. The router is powered by a dual-core Intel Xeon processor and has 2GB of RAM and 8GB of flash memory, making it capable of handling a wide range of routing, security, and data services applications. It also supports Cisco IOS XE software, which provides a flexible and scalable platform for implementing advanced routing and services functions.

Some of the key features of the Cisco ISR 4321 include:

  • Support for a wide range of connectivity options, including Ethernet, serial, and WAN interface cards.
  • Integration with Cisco security technologies, such as firewall, VPN, and content filtering.
  • Advanced Quality of Service (QoS) features for optimizing voice and video traffic.
  • Support for Cisco IOS XE software, which provides a flexible and scalable platform for implementing advanced routing and services functions.
  • Integration with Cisco Network Assistance, a powerful tool for managing and configuring the router.
  • Support for a range of applications, including routing, security, voice, and video.

High Availability Features of the ISR4321/K9 Cisco ISR 4321 Router

The Cisco ISR 4321 security router supports several high availability (HA) features that help ensure continuous network operation in the event of a hardware or software failure. Some of the key HA features supported by the ISR 4321 include:

  • Stateful Switchover (SSO): This feature provides a mechanism for the router to switch over to a standby processor in the event of a primary processor failure. The standby processor maintains a synchronized state with the primary processor, so there is no loss of data during the switchover.
  • Hot Standby Router Protocol (HSRP): This feature provides automatic failover for IP networks by allowing a set of routers to share a virtual IP address. In the event of a router failure, the standby router can take over the virtual IP address and continue forwarding packets.
  • Virtual Router Redundancy Protocol (VRRP): Similar to HSRP, VRRP allows a set of routers to share a virtual IP address. However, VRRP allows for more than two routers to participate in the redundancy group, providing greater scalability.
  • Gateway Load Balancing Protocol (GLBP): This feature provides load balancing and redundancy for IP traffic by allowing multiple routers to share a virtual IP address. GLBP can distribute traffic across multiple paths, and can also provide automatic failover in the event of a router failure.
  • Network Address Translation (NAT) redundancy: This feature provides redundancy for NAT configurations by allowing multiple routers to share NAT translations. If one router fails, the other router can take over the NAT translations.
  • To implement these HA features on the Cisco ISR 4321, you will need to follow the specific configuration instructions provided by Cisco. The configuration guides and documentation available on the Cisco website provide step-by-step instructions on how to configure these features on the ISR 4321. It is also recommended to consult with a Cisco-certified network engineer for assistance with configuring high availability on your network.

WAN Connectivity Options of the ISR4321/K9 Cisco ISR 4321 Router

The Cisco ISR 4321 router is a highly capable network device that offers a range of WAN connectivity options to suit different requirements. Some of the WAN connectivity options available for the ISR 4321 include:

  • Ethernet WAN: The ISR 4321 router comes with two built-in Gigabit Ethernet WAN ports that can be used to connect to high-speed broadband Internet services. These ports can be used with different types of WAN technologies, including DSL, cable, and fiber.
  • T1/E1 WAN: The ISR 4321 also supports T1/E1 WAN connectivity using the built-in HWIC-2T1/E1 module. This allows for the use of leased lines or other types of dedicated circuits for WAN connectivity.
  • Serial WAN: The ISR 4321 can also support legacy serial WAN connectivity using the built-in HWIC-2T module. This allows for the use of synchronous or asynchronous serial connections for WAN connectivity.
  • LTE Wireless WAN: The ISR 4321 can support wireless WAN connectivity using a Cisco LTE module, such as the Cisco EHWIC-4G-LTE or Cisco EHWIC-4G-LTE-G. This allows for high-speed mobile broadband connectivity using cellular networks.
  • Satellite WAN: The ISR 4321 can also support satellite WAN connectivity using the built-in HWIC-4B-S/T module. This allows for the use of satellite-based connectivity for remote sites or locations where terrestrial connectivity is not available.
  • To determine the most appropriate WAN connectivity option for your network, you should consider factors such as bandwidth requirements, geographic location, availability of service providers, and cost. It may also be helpful to consult with a Cisco-certified network engineer to help you evaluate your options and design a network that meets your specific needs.

General Information about the Cisco ISR4321/K9

  • Manufacturer: Cisco
  • Part Number or SKU # ISR4321/K9
  • Product Series: 4000
  • Product Model: 4321
  • Product Name: 4321 Router
  • Product Type: Router

Technical Information of Router 4000 Series

  • Total Number of Ports: 2
  • USB: Yes
  • Powerline: No
  • Management Port: Yes
  • Serial V.35 Interface: No
  • Number of Network (RJ-45) Ports: 2

I/O Expansions for 2 Ports Integrity Service Router

  • Number of Total Expansion Slots: 4
  • Expansion Slot Type: Smart Interface Card (SIC)
  • Expansion Slot Type: Network Interface Module (NIM)
  • Expansion Slot Type: SFP

Network & Communication of SFP Router

  • Network Technology: 10/100/1000Base-T
  • Ethernet Technology: Gigabit Ethernet

Management & Protocols

  • Security Features:
  • ACL
  • AAA
  • IPsec

Memory ISR4321 K9

  • Standard Memory: 4 GB
  • Maximum Memory: 8 GB
  • Memory Technology: DDR3 SDRAM
  • Flash Memory: 4 GB
Power Description
  • Input Voltage 230 V AC
  • Input Voltage 120 V AC
  • Power Source PoE
  • Power Source Power Supply
  • Redundant Power Supply No

In Summary, the Cisco ISR4321/K9 Integrated Service Router is a powerful and versatile networking solution for businesses and organizations. With its high-performance routing, security features, and flexibility in mounting options, it's an ideal choice for meeting the demands of modern networking. Whether you need a secure and scalable router for a small office or a data center, the ISR4321/K9 has you covered. Invest in the Cisco ISR4321/K9 for a dependable and efficient network infrastructure.

Product Condition:
Warranty provided by ALLHDD.COM:
90 Days

About Refurbished Products

Refurbished products are typically refurbished by an Original Manufacturer or an affiliate of the manufacturer or 3rd party facility. This product may have minor blemishes due to normal product usage and doesn't necessarily come with documentation and software unless indicated, but has been well tested and generally has never had any defects.

Here, you can check more available conditions of your desired product ISR4321/K9 at a competitive price. We are trying our best to meet your needs on the enterprise-level computer, server, data centre, and networking hardware. You are welcome to ask our live chat or get live representative support over the phone.


Please choose your location for calculate shipping cost.


ALLHDD guarantees that the products will not have defects in material that will affect the product's functionality during the Standard Warranty Period. The warranty period starts when the merchandise/items from our warehouse.

What does ALLHDD.Com warranty cover?

30-days to 3 years warranty:

Replacement or refund. In the case of material defects, we will try to replace the product first. The product will be replaced before the expiration of the original warranty. For any failure of hardware, if we cannot process the replacement of the product(s)/model(s), we will refund the original selling/invoiced price. The shipping costs and sales tax, if any, are non-refundable. ALLHDD retains the right to decide whether the item(s) will process for replacement or refund.

What is not covered by our warranty?

The reason why our warranty does not cover any problem caused by the following conditions:

(a) misuse of hardware; accidental damage; carelessness product(s) damage; shock; temperature beyond the specification of any product; faulty installation; operation; modification of goods;

(b) any misuse outside the instructions in the user manual for any specific product;

(c) damaged caused by other hardware or equipment. The warranty will void if the item is returned with physical damage, damage to the retail box, removed from the box, counterfeit labels/labelled by them, or any modifications of internal and external covers. Data loss or damages to any other equipment we do not cover by our offered warranty.

What is the Manufacturer/Brand Warranty?

In general, a manufacturer's warranty service/support is a written guarantee to the buyer of a product. Its terms assure the replacement or repair of the product, if necessary, within a specified period after the purchase (2-5 years depending on the brand/manufacturer). It is typically included in the price of the product. Products are brand new and sealed and the original manufacturer box is complete with the Manufacturer's genuine warranty. For most of the brand new/retail products that come with the manual and box, exceptions may apply (i.e., Cisco, Juniper Networks).

For the server parts (i.e., Dell, HPE) to get Full coverage of the warranty server must have a full 3- 5 years warranty. However, ALLHDD.COM will cover the warranty duration if any Manufacturer doesn't support the advertised warranty and there is no refund for those.
Final Sale items are non-returnable/refundable in any situation. Any question? please ask our team before the shipment.

Important notes:

We can provide additional warranty service/support for any product you purchase from us if you need additional warranty coverage before finalizing the order from ALLHDD.Com. You need to ask in live chat/help or call us for more information.

Individual product warranty mentioned on each item product description page/detail page.

Free Technical support on purchased items, our expert consultancy over the phone, by email, by live chat, or by remote login.


Shipping Options and Estimated Delivery Time

UPS Shipping Options:

FREE UPS® Ground (Free shipping to all orders for 48 states!)
Estimated delivery time: 4-7 business days

UPS 3 Day Select®
Estimated delivery time: 3 business days

UPS 2nd Day Air®
Estimated delivery time: 1-2 business days, Delivery by 10:30 AM or 2:00 PM

UPS Next Day Air® Standard Overnight
Estimated delivery time: Overnight 2-5 PM, Standard Overnight Delivery.

UPS Next Day Air® - Priority Overnight
Estimated delivery time: Overnight Delivery (Next Business Day) Delivery by 10:30 AM or 12:00 PM

UPS Next Day Air® First Overnight - Early A.M
Estimated delivery time: Overnight 8:00 AM, Early morning, overnight delivery for your time-critical shipments.

UPS® First Overnight - Saturday
Estimated delivery time: Overnight 8:30 AM – Saturday

FedEx Shipping Options:

FedEx Ground®
Estimated delivery time: (4–7 business days in the contiguous 48 states)
*For residential delivery via FedEx Ground use FedEx Home Delivery®
Estimated delivery time: 4−7 business days, based on the distance to the destination.

FedEx Express Saver®
Estimated delivery time: 3 business days (by 4:30 PM to U.S. businesses; by 8:00 PM to residences)
Available throughout all 50 states (except Hawaii and Alaska)

FedEx 2Day®
Estimated delivery time: 2 business days (by 4:30 PM to U.S. businesses; by 8:00 PM to residences)
Available throughout all 50 states

FedEx Standard Overnight®
Estimated delivery time: Next-business-day (by 4:30 PM to U.S. businesses and by 8:00 PM to residences)
Available throughout all 50 states (Hawaii is outbound only)

FedEx Priority Overnight®
Estimated delivery time: Next-business-day (by 10:30 PM to U.S. businesses, noon to most residences)
Available throughout all 50 states

FedEx First Overnight®
Estimated delivery time: Next-business-day (by 8:30 or 9 AM to most areas)
Available throughout all 50 states

Worldwide Shipping Options:

UPS®/FedEx® International Economy

Estimated delivery time: 4-7 business days

UPS®/FedEx® International Priority

Estimated delivery time: 2-4 business days

UPS®/FedEx® Ground Shipping Canada

Estimated delivery time: 5-8 business days

Important notes:

  • The processing of orders with Ground Shipping can take up to 24-48 hours. But we try to process all orders the same day.
  • We are not responsible for weather problems that may affect the delivery of goods by carriers. We cannot guarantee the exact delivery time, regardless of the carriers' claims.
  • If you have any specific delivery time requirements, please contact our customer support and someone from our customer service team will be able to help you.
  • You can estimate the shipping cost from the products detail page, also available on the checkout page
  • The shipping cost depends on box dimensions, weight, and zip/postal code
  • To get a FedEx® delivery service you need to mention it on the checkout page notebox.
  • For urgent shipments, please contact our customer service.
  • Shipping cut off 4:00 PM (Monday-Friday) and available blind drop shipment.