Frame Tagging

George S. georges at mhsoftware.com
Wed Jul 24 18:32:07 UTC 2013


I'm using DHCP 4.2.5 on a linux machine running kernel version 3.7.10

I've got the eth0 interface setup using Frame Tagging.  I've got a 
secondary interface eth0.2 running the network 172.22.0.0. There is only 
one physical network. The frame tagging is getting done by a wifi access 
point. Anything coming over the open wifi network should be coming in 
with the frame tagged for id 2. The problem is that DHCP seems to be 
doing things wrong. It's looking to me like it's ignoring the frame 
tagging and it's processing the DHCP request on both interfaces. So, I'm 
getting people from the public wifi on the wrong network.

I've searched and looked through old messages on this topic, but I've 
never found anything that looked like either a solution or a definitive 
pronouncement that it just can't work.

I've looked through the docs and I saw the comment about frame tagging 
and vconfig. I implemented that but it makes no difference.

Here are some messages in my log:

2013-07-22T13:17:29.121349-06:00 server dhcpd: DHCPOFFER on 
172.22.13.223 to 84:29:99:7c:7e:fa (Karas-iPhone) via eth0.2
2013-07-22T13:17:29.121389-06:00 server dhcpd: DHCPOFFER on 10.1.10.95 
to 84:29:99:7c:7e:fa (Karas-iPhone) via eth0
2013-07-22T13:17:30.202147-06:00 server dhcpd: DHCPREQUEST for 
172.22.13.223 (172.22.0.32) from 84:29:99:7c:7e:fa (Karas-iPhone) via eth0.2
2013-07-22T13:17:30.202381-06:00 server dhcpd: DHCPACK on 172.22.13.223 
to 84:29:99:7c:7e:fa (Karas-iPhone) via eth0.2
2013-07-22T13:17:30.202594-06:00 server dhcpd: DHCPREQUEST for 
172.22.13.223 (172.22.0.32) from 84:29:99:7c:7e:fa (Karas-iPhone) via 
eth0: wrong network.
2013-07-22T13:17:30.202753-06:00 server dhcpd: DHCPNAK on 172.22.13.223 
to 84:29:99:7c:7e:fa via eth0



Here's my dhcpd.conf

authoritative;
option domain-search "crossingchurch.org", "wcon.org", "private.wcon.org";
ddns-update-style interim;
deny client-updates;

log-facility local7;


key DHCP_UPDATER {
	algorithm hmac-md5;
	secret "1hamjDWV1PIwTdmwRfLjezhrxkTpm1RqRAXaecLJ548=";
}

zone private.wcon.org {
	primary 127.0.0.1;
	key DHCP_UPDATER;
}

zone 10.1.10.in-addr.arpa {
	primary 127.0.0.1;
	key DHCP_UPDATER;
}

host sign.private.wcon.org {
	hardware ethernet 00:20:4a:8e:e2:8c;
	fixed-address 10.1.10.40;
}

subnet 10.1.10.0 netmask 255.255.255.0 {
	option domain-name "private.wcon.org";
	ddns-updates on;
	option domain-name-servers 10.1.10.32;
	option routers 10.1.10.1;
	option ntp-servers 10.1.10.32;
	range 10.1.10.64 10.1.10.254 ;
	default-lease-time 252900;
	max-lease-time 252900;
	option netbios-name-servers 10.1.10.32;
}

subnet 172.22.0.0 netmask 255.255.0.0 {
	option domain-name "pubwifi.crossingchurch.org";
	ddns-updates off;
	option domain-name-servers 172.22.0.32;
	option routers 172.22.0.32;
	option ntp-servers 172.22.0.32;
	range 172.22.2.0 172.22.254.254 ;
	default-lease-time 43200;
	max-lease-time 43200;
}




-- 
George Sexton
MH Software, Inc.
303 438-9585
http://www.mhsoftware.com/



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