Discussion:
DHCP 4.0.2, execute() and hardware address mismatch
(too old to reply)
Sławomir Paszkiewicz
2010-10-11 09:40:36 UTC
Permalink
Hello,
I`m trying to migrate from DNSMasq to ISC DHCP because of failover.
My problem is that MAC Addresses (hardware) are in different format than
iptables accept (i`m executing script via execute() which call iptables
-A FORWARD -m mac --mac-source .... -j ACCEPT).

In ISC DHCP logs format is correct:

DHCPREQUEST for 10.59.146.180 from 00:d0:b8:0c:ba:d8 via eth0

But 'hardware' (i`m using binary-to-ascii(16, 8, ":",
substring(hardware,1, 6));) gives me:

0:d0:b8:c:ba:d8 which is incorrect for iptables:

# iptables -A FORWARD -m mac --mac-source 0:d0:b8:c:ba:d8 -s
10.59.146.180 -j ACCEPT
iptables v1.4.4: Bad mac address "0:d0:b8:c:ba:d8"

My question is how to get correct (for iptables) format (same as in dhcp
logs) ?

Best regards,
paszczus
Patricio Latini
2010-10-11 14:49:58 UTC
Permalink
Thy this

concat (suffix (concat ("0", binary-to-ascii (16, 8, "", substring(hardware,
1, 1))),2),":",suffix (concat ("0", bi
nary-to-ascii (16, 8, "", substring(hardware, 2, 1))),2),":",suffix (concat
("0", binary-to-ascii (16, 8, "", substring(hardware, 3, 1))),2),":",
suffix (concat ("0", binary-to-ascii (16, 8, "", substring(hardware, 4,
1))),2),":",suffix (concat ("0", binary-to-ascii (16, 8, "", substring(h
ardware, 5, 1))),2),":",suffix (concat ("0", binary-to-ascii (16, 8, "",
substring(hardware, 6, 1))),2));

Patricio

-----Original Message-----
From: dhcp-users-bounces+p_latini=***@lists.isc.org
[mailto:dhcp-users-bounces+p_latini=***@lists.isc.org] On Behalf Of
Slawomir Paszkiewicz
Sent: Monday, October 11, 2010 6:41 AM
To: dhcp-***@lists.isc.org
Subject: DHCP 4.0.2, execute() and hardware address mismatch

Hello,
I`m trying to migrate from DNSMasq to ISC DHCP because of failover.
My problem is that MAC Addresses (hardware) are in different format than
iptables accept (i`m executing script via execute() which call iptables
-A FORWARD -m mac --mac-source .... -j ACCEPT).

In ISC DHCP logs format is correct:

DHCPREQUEST for 10.59.146.180 from 00:d0:b8:0c:ba:d8 via eth0

But 'hardware' (i`m using binary-to-ascii(16, 8, ":",
substring(hardware,1, 6));) gives me:

0:d0:b8:c:ba:d8 which is incorrect for iptables:

# iptables -A FORWARD -m mac --mac-source 0:d0:b8:c:ba:d8 -s
10.59.146.180 -j ACCEPT
iptables v1.4.4: Bad mac address "0:d0:b8:c:ba:d8"

My question is how to get correct (for iptables) format (same as in dhcp
logs) ?

Best regards,
paszczus
Sławomir Paszkiewicz
2010-10-11 15:58:53 UTC
Permalink
Yeah! Works like a charm!

Thanks a lot Patricio!
Post by Patricio Latini
Thy this
concat (suffix (concat ("0", binary-to-ascii (16, 8, "", substring(hardware,
1, 1))),2),":",suffix (concat ("0", bi
nary-to-ascii (16, 8, "", substring(hardware, 2, 1))),2),":",suffix (concat
("0", binary-to-ascii (16, 8, "", substring(hardware, 3, 1))),2),":",
suffix (concat ("0", binary-to-ascii (16, 8, "", substring(hardware, 4,
1))),2),":",suffix (concat ("0", binary-to-ascii (16, 8, "", substring(h
ardware, 5, 1))),2),":",suffix (concat ("0", binary-to-ascii (16, 8, "",
substring(hardware, 6, 1))),2));
Patricio
-----Original Message-----
Slawomir Paszkiewicz
Sent: Monday, October 11, 2010 6:41 AM
Subject: DHCP 4.0.2, execute() and hardware address mismatch
Hello,
I`m trying to migrate from DNSMasq to ISC DHCP because of failover.
My problem is that MAC Addresses (hardware) are in different format than
iptables accept (i`m executing script via execute() which call iptables
-A FORWARD -m mac --mac-source .... -j ACCEPT).
DHCPREQUEST for 10.59.146.180 from 00:d0:b8:0c:ba:d8 via eth0
But 'hardware' (i`m using binary-to-ascii(16, 8, ":",
# iptables -A FORWARD -m mac --mac-source 0:d0:b8:c:ba:d8 -s
10.59.146.180 -j ACCEPT
iptables v1.4.4: Bad mac address "0:d0:b8:c:ba:d8"
My question is how to get correct (for iptables) format (same as in dhcp
logs) ?
Best regards,
paszczus
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https://lists.isc.org/mailman/listinfo/dhcp-users
Glenn Satchell
2010-10-11 16:43:31 UTC
Permalink
Post by Sławomir Paszkiewicz
Yeah! Works like a charm!
Thanks a lot Patricio!
Post by Patricio Latini
Thy this
concat (suffix (concat ("0", binary-to-ascii (16, 8, "", substring(hardware,
1, 1))),2),":",suffix (concat ("0", bi
nary-to-ascii (16, 8, "", substring(hardware, 2, 1))),2),":",suffix (concat
("0", binary-to-ascii (16, 8, "", substring(hardware, 3, 1))),2),":",
suffix (concat ("0", binary-to-ascii (16, 8, "", substring(hardware, 4,
1))),2),":",suffix (concat ("0", binary-to-ascii (16, 8, "", substring(h
ardware, 5, 1))),2),":",suffix (concat ("0", binary-to-ascii (16, 8, "",
substring(hardware, 6, 1))),2));
Patricio
-----Original Message-----
Slawomir Paszkiewicz
Sent: Monday, October 11, 2010 6:41 AM
Subject: DHCP 4.0.2, execute() and hardware address mismatch
Hello,
I`m trying to migrate from DNSMasq to ISC DHCP because of failover.
My problem is that MAC Addresses (hardware) are in different format than
iptables accept (i`m executing script via execute() which call iptables
-A FORWARD -m mac --mac-source .... -j ACCEPT).
DHCPREQUEST for 10.59.146.180 from 00:d0:b8:0c:ba:d8 via eth0
But 'hardware' (i`m using binary-to-ascii(16, 8, ":",
# iptables -A FORWARD -m mac --mac-source 0:d0:b8:c:ba:d8 -s
10.59.146.180 -j ACCEPT
iptables v1.4.4: Bad mac address "0:d0:b8:c:ba:d8"
My question is how to get correct (for iptables) format (same as in dhcp
logs) ?
Best regards,
paszczus
It's amazing, I created this construction in 2003, and it just keeps
coming back! Maybe I should print a t-shirt - no-one apart from the
subscribers to this list would understand it :)

Original post is here, with slightly easier to read formatting. Glad to
see it is still being found useful,

http://marc.info/?l=dhcp-server&m=105689607527110&w=2

Maybe dhcpd needs a "sprintf" statement to handle this a bit more
elegantly - think of a % escape that formats a binary representation of
hardware or ip-address to a printable... It's also a bit poor that
iptables expects leading zeroes in a mac address.
--
regards,
-glenn
--
Glenn Satchell | Miss 9: What do you
Uniq Advances Pty Ltd, Sydney Australia | do at work Dad?
mailto:***@uniq.com.au | Miss 6: He just
http://www.uniq.com.au tel:0409-458-580 | types random stuff.
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