ISP-2 will only be used when ISP-1 goes offline. When ISP-1 comes back online we will switch back over to ISP-1. So let's first look at getting the ASA HA pair setup. In this example I have two ASA's that are the same hardware and software version, For the HA I have to be able to use two interfaces for the LAN failover and State link interface. As for the ISP failover/traffic splitting there are varying configuration possiblities. The simplest, is to just modify your static routes to include a qualified-next-hop. Again, there are several ways to configure the actual failover/HA portion between your ISPs but clustering your SRXs and connecting both ISPs to them is the best redundancy. Dual ISP NAT Failover Not Working. Ask Question Asked 3 years, 7 months ago. Active 3 years, 6 months ago. Viewed 999 times 3. I have a Cisco 1841 router with an HWIC-4ESW switchport module attached to it. Fa0/0 is connected to ISP1 and Fa0/1 to ISP2 and both are 'ip nat outside', the switchports are in interface Vlan 1, which has an IP address. Dual Internet connections Secondary IP addresses to an interface Software switch. Network address translation (NAT) Configuring SNAT Configuring DNAT VLANs and forwarding domains. SIP and HA–session failover and geographic redundancy.
I have a ASA5545-X with this configuration (gigabit primary and 50 Mbps as a backup). When you switch over to the backup ISP based on the routing metric the external IP addresses have to be different as it is a different ISP or connection so you won't be able to have uninterrupted inbound connections.
When the circuits were first installed we had fail-overs several times a day but since I disconnected the ISP's router and connected the ONT directly to the ASA as much as a year ago now, it hasn't failed over even once so you will likely find, as I did, that this nice to have really isn't necessary anyways.
If you are running an email server you will likely have to use policy based routing (PBR) to force the email traffic to one connection or the other, I certainly had to, oh, forget that, I see you are using a 5505 and it doesn't do PBR :)
Make sure you have 9.2(4.5) or later lest you be vulnerable to CVE-2016-1287.
This post describes how to configure a Cisco ASA firewall for redundant/dual ISP connections, using the IP SLA and track features. IP SLA will be configured in conjunction with the track feature to monitor the connection/reachability to the Primary ISP connection. In the event of failure, the primary default route will be removed and will failover to a backup route.
Configuration
Configure the 2 outside interfaces, in this case PRIMARY and SECONDARY will be used to identify the outside interfaces.
Create nat rules for traffic routed out of the primary and secondary interfaces.
Create an SLA monitoring process, which will periodically send ICMP echo requests to the IP address of the next hop (ISP router) and from the primary interface.
Schedule the SLA process to start immediately with a lifetime of forever.
Create a track ID, the 'rtr' references the SLA ID. The track ID will be used in conjunction with static default route.
Nat Failover With Dual Isp Router
Define a default route via the PRIMARY interface, referencing the track object.
Create a backup default route via the SECONDARY interface with an administrative distance greater than the tracked default route.
Verification
From a test computer ping an IP address on the internet, e.g. 8.8.8.8
Confirm traffic is being routed out of the PRIMARY interface
Confirm that traffic is hitting the correct NAT rule
Confirm the status of the IP SLA enter the command show sla monitor operational-state, ensure timeout equals FALSE.
Confirm that reachabilty of the track is Up, use the command show track
Shutdown the interface of the PRIMARY interface
Confirm the status of the reachability of the track is Down
Nat Failover With Dual Isp Connection
Nat Failover With Dual Isp Dhcp
Confirm the default route is now via the SECONDARY interface.
Confirm traffic is natted by the correct NAT rule
ISP-2 will only be used when ISP-1 goes offline. When ISP-1 comes back online we will switch back over to ISP-1. So let's first look at getting the ASA HA pair setup. In this example I have two ASA's that are the same hardware and software version, For the HA I have to be able to use two interfaces for the LAN failover and State link interface. As for the ISP failover/traffic splitting there are varying configuration possiblities. The simplest, is to just modify your static routes to include a qualified-next-hop. Again, there are several ways to configure the actual failover/HA portion between your ISPs but clustering your SRXs and connecting both ISPs to them is the best redundancy. Dual ISP NAT Failover Not Working. Ask Question Asked 3 years, 7 months ago. Active 3 years, 6 months ago. Viewed 999 times 3. I have a Cisco 1841 router with an HWIC-4ESW switchport module attached to it. Fa0/0 is connected to ISP1 and Fa0/1 to ISP2 and both are 'ip nat outside', the switchports are in interface Vlan 1, which has an IP address. Dual Internet connections Secondary IP addresses to an interface Software switch. Network address translation (NAT) Configuring SNAT Configuring DNAT VLANs and forwarding domains. SIP and HA–session failover and geographic redundancy.
I have a ASA5545-X with this configuration (gigabit primary and 50 Mbps as a backup). When you switch over to the backup ISP based on the routing metric the external IP addresses have to be different as it is a different ISP or connection so you won't be able to have uninterrupted inbound connections.
When the circuits were first installed we had fail-overs several times a day but since I disconnected the ISP's router and connected the ONT directly to the ASA as much as a year ago now, it hasn't failed over even once so you will likely find, as I did, that this nice to have really isn't necessary anyways.
If you are running an email server you will likely have to use policy based routing (PBR) to force the email traffic to one connection or the other, I certainly had to, oh, forget that, I see you are using a 5505 and it doesn't do PBR :)
Make sure you have 9.2(4.5) or later lest you be vulnerable to CVE-2016-1287.
This post describes how to configure a Cisco ASA firewall for redundant/dual ISP connections, using the IP SLA and track features. IP SLA will be configured in conjunction with the track feature to monitor the connection/reachability to the Primary ISP connection. In the event of failure, the primary default route will be removed and will failover to a backup route.
Configuration
Configure the 2 outside interfaces, in this case PRIMARY and SECONDARY will be used to identify the outside interfaces.
Create nat rules for traffic routed out of the primary and secondary interfaces.
Create an SLA monitoring process, which will periodically send ICMP echo requests to the IP address of the next hop (ISP router) and from the primary interface.
Schedule the SLA process to start immediately with a lifetime of forever.
Create a track ID, the 'rtr' references the SLA ID. The track ID will be used in conjunction with static default route.
Nat Failover With Dual Isp Router
Define a default route via the PRIMARY interface, referencing the track object.
Create a backup default route via the SECONDARY interface with an administrative distance greater than the tracked default route.
Verification
From a test computer ping an IP address on the internet, e.g. 8.8.8.8
Confirm traffic is being routed out of the PRIMARY interface
Confirm that traffic is hitting the correct NAT rule
Confirm the status of the IP SLA enter the command show sla monitor operational-state, ensure timeout equals FALSE.
Confirm that reachabilty of the track is Up, use the command show track
Shutdown the interface of the PRIMARY interface
Confirm the status of the reachability of the track is Down
Nat Failover With Dual Isp Connection
Nat Failover With Dual Isp Dhcp
Confirm the default route is now via the SECONDARY interface.
Confirm traffic is natted by the correct NAT rule
Cisco Nat Failover Dual Isp
Re-establishing connectivity via the PRIMARY interface will result in the default route via the PRIMARY interface being installed in the routing table.