Article ID: 14966
Products
G-Series, firmware 6.42.10.0016 through 6.61.08.0013
C5-Series; firmware 6.42.10.0016 through 6.61.08.0013, 6.71.01.0067 through 6.71.02.0008
C3-Series, firmware 6.42.10.0016 through 6.61.08.0013
B5-Series; firmware 6.42.10.0016 through 6.61.08.0013, 6.71.01.0067 through 6.71.02.0008
A4-Series; firmware 6.61.02.0007 through 6.61.08.0013, 6.71.01.0067 through 6.71.02.0008
Changes
Used the 'ip helper-address...' command to configure two or more IP Helpers (
5720) onto the local router process, under a total of one or more VLAN interfaces.
Used the 'no ip helper-address...' command to delete one of the IP Helper entries.
Symptoms
The IP Helper is not forwarding certain broadcast traffic as it should.
DHCP and other configured 'ip forward-protocol...' features (
11980) are not operating beyond the source subnet.
The issue affects all VLAN interfaces on the router.
Solution/Workaround
Upgrade to 6.61 firmware 6.61.09.0012 or higher.
Release notes state, in the 'Changes and Enhancements in 6.61.09.0012' section:
18103 Corrected an issue where removing an IP Helper address from one interface prevented its use globally.
Also fixed as of C5/B5/A4-Series firmware 6.71.03.0025 (though not stated in release notes).
Pre-upgrade workaround:
Add another 'ip helper-address...' command to any routed VLAN interface, even if the address already exists ("Error: IP Address is already configured on this router interface").
This can as desired specify a "dummy" IP address, such as "1.1.1.1".
