Question : Cisco router as dhcp relay agent

Hi

Can cisco routers eg 2600 series routers act as DHCP relay agent or something needs to configured on them?

Answer : Cisco router as dhcp relay agent

Yes, using the "ip helper-address" command on the ethernet interface facing the LAN without the DHCP server.

router>en
Password:
router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
router(config)#interface ethernet0
router(config-if)#ip helper-address 192.168.0.10

All DHCP broadcasts that hit the ethernet interface will be forwarded as unicasts to the DHCP server address specified in the IP helper address command.  The command is only needed on the interface attached to the LAN without the DHCP server.