[ale] problems running dhcrelay

[J. Patrick Graves]

I am trying to manage dhcp clients on multiple subnets from one dhcpd server.  To do this you
need to relay the dhcp request from the subnets to the central dhcpd server.  However, after
trying everything I could think of (e.g. standing on one foot and pressing enter with my left
pinky) I finally got dhcrelay to work properly.  I was originally writing this message to ask
for help, but now I guess my question is why did this work?

I'm running RedHat 6.0 and I using the dhcrelay that comes with dhcp rpm package.
(dhcp-2.0b1p6-6).  I have recompiled the kernel, mainly taking out hardware specific modules.
I have an Adaptec Quartet 4 port 10/100 card and a Netgear 10/100 tulip card.
eth0 is on the NetGear and eth1-4 are on the Quartet.  All networks route appropriately.


Originally, when I started dhcrelay, I got the following messages:
---
[root at gw1 root]$ /usr/sbin/dhcrelay -d dhcpserver
Listening on Socket/eth4/unattached
Sending on   Socket/eth4/unattached
Listening on Socket/eth3/unattached
Sending on   Socket/eth3/unattached
Listening on Socket/eth2/unattached
Sending on   Socket/eth2/unattached
Listening on Socket/eth1/unattached
Sending on   Socket/eth1/unattached
Listening on Socket/eth0/unattached
Sending on   Socket/eth0/unattached
---

And when dhcrelay received a dhcp request the following message was displayed

---
forwarded BOOTREQUEST for 0a:0a:51:cc:26:0e to 192.168.1.253
---

But nothing was received by dhcpd on dhcpserver.

When I did a tcpdump on all of the ethernet devices on my gateway, I saw that the request was
not being forwarded.  Instead, I saw three arp who-has requests for the dhcpd server
(192.168.1.253) ON THE WRONG DEVICE!  The arp request should have been on eth0 but was on
eth4.

I specified the ethernet devices on the command line like so and everything worked fine:

---
[root at gw1 root]$ /usr/sbin/dhcrelay -d dhcpserver -i eth4 -i eth3 -i eth2 -i eth1 -i eth0
Listening on Socket/eth0/unattached
Sending on   Socket/eth0/unattached
Listening on Socket/eth1/unattached
Sending on   Socket/eth1/unattached
Listening on Socket/eth2/unattached
Sending on   Socket/eth2/unattached
Listening on Socket/eth3/unattached
Sending on   Socket/eth3/unattached
Listening on Socket/eth4/unattached
Sending on   Socket/eth4/unattached
---

I guess that this is a dhcrelay problem, but I haven't looked at the code.

J. Patrick Graves

p.s. how do I report this as a bug?