HSRP + ip helper-address reduncancy option between IOS-XE and IOS

[mhiyoshi]

Dear all,

Anyone knows alternative solution about ip-helper-address redundancy + HSRP on IOS-XE?

Because the following is difference between IOS-XE and IOS. Normally IOS-Router can be configurable the ip-helper-address with redundancy option however IOS-XE can not be possible.

C1111-IOS-XE(config-if)#ip helper-address 1.1.1.1 ?
  <cr>  <cr>

C921J-IOS(config-if)#ip helper-address 1.1.1.1 ?
  redundancy  defines VRG group name
  <cr>

In my opinion at least HSRP state log can be generate on the HSRP standby router so EEM can be possible right?

%HSRP-5-STATECHANGE: Grp 1 state Standby -> Active
* Then EEM Start to configure ip helper-address 1.1.1.1
* If HSRP Active Router recover from failure then delete this configuration.

Best Regards,

Masanobu Hiyoshi

[MHM Cisco World]

Yes I think you can use EEM for this case 

[M02@rt37]

Hello @mhiyoshi 

In IOS-XE, there are a few alternatives that can be used to achieve redundancy for the ip-helper-address and HSRP configuration:

- Use the "ip dhcp relay address" command instead of "ip helper-address". This command is supported in IOS-XE and allows for redundancy by configuring multiple IP addresses for the DHCP server:

interface GigabitEthernet0/0/0
ip dhcp relay address 10.1.1.1 10.1.1.2
standby 1 ip 10.1.1.3

This configuration sets up the DHCP relay to forward DHCP requests to both 10.1.1.1 and 10.1.1.2, and sets up HSRP with a virtual IP of 10.1.1.3.

[mhiyoshi]

Hi  M02@rt37,

Thank you for your information. I have a question about which version can configure "ip dhcp relay address"?
 I appreciate if you can let me know the IOS-XE Version and H/W like ISR4K 1K or ASR1K etc..

Regards,

Masanobu Hiyoshi

[M02@rt37]

Hello @mhiyoshi 

This command is available on a wide range of Cisco devices, including the ISR4K, ASR1K, and many others.

The specific IOS-XE version that supports the "ip dhcp relay address" command may vary depending on the device model and platform. However, this command is a standard feature in most Cisco IOS releases, including IOS-XE 16.9 and later.

To be more specific, here are some examples of IOS-XE versions that support "ip dhcp relay address" on certain devices:

- ISR 4000 series: IOS-XE 3.14S and later.

- ASR 1000 series: IOS-XE 3.11S and later.