DHCP relay does not work with
cl-mgmtvrf when the host and server facing ports are in the data plane.
- Cumulus Linux 2.5.4 or 2.5.5
cl-mgmtvrfpackage versions earlier than
isc-dhcp-relaypackage versions earlier than
- DHCP relaying from one dataplane interface to another dataplane interface.
Upgrade to Cumulus Linux 2.5.6 with
isc-dhcp-relay=4.2.2.dfsg.1-5+deb70u6+cl2+3 or later. For more information, see RN-370.
Configuration Work Around
For switches running CL 2.5.4 or CL 2.5.5.
On the switch running
dhcprelay, add an IP rule for the DHCP server address. Replace
SERVER_IP with the
value specified in
cumulus@switch$ sudo ip rule add from all to SERVER_IP lookup main
This rule can be applied at boot time, by specifying it in an
up rule on the corresponding interface. The example below applies the
172.16.0.1 to interface
auto swp52 iface swp52 address 172.16.0.2/24 up ip rule add from all to 172.16.0.1 lookup main
tcpdumpfrom the switch on the host and server facing ports to trace traffic.
Stop the dhcprelay service.
cumulus@switch:~$ sudo service isc-dhcp-relay stop
Run the dhcprelay service in the foreground on the console to watch the output while issuing requests. The output below is an example of a successful session:
cumulus@switch:~$ sudo /usr/sbin/dhcrelay -d -i swp51 -i swp52 172.16.0.1 Internet Systems Consortium DHCP Relay Agent 4.2.2 Copyright 2004-2011 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/swp2/44:38:39:00:25:d9 Sending on LPF/swp2/44:38:39:00:25:d9 Listening on LPF/swp1/44:38:39:00:25:d8 Sending on LPF/swp1/44:38:39:00:25:d8 Sending on Socket/fallback Forwarded BOOTREQUEST for 68:05:ca:2f:7c:b3 to 172.16.0.1 Forwarded BOOTREPLY for 68:05:ca:2f:7c:b3 to 172.16.1.128 Forwarded BOOTREPLY for 68:05:ca:2f:7c:b3 to 172.16.1.128 Forwarded BOOTREQUEST for 68:05:ca:2f:7c:b3 to 172.16.0.1 Forwarded BOOTREPLY for 68:05:ca:2f:7c:b3 to 172.16.1.128 Forwarded BOOTREPLY for 68:05:ca:2f:7c:b3 to 172.16.1.128