Folks
This might be the wrong place to ask, but I don't know where to turn.
My internal home network, including wireless, is controlled by a
Centos6 server, which provides dhcpd services, along with NAT. I
have DHCPD configured with the addresses 192.168.155.200 through
192.168.155.254 as the range for dynamic allocations. The
default-lease time is 1800 seconds, the maximum is 3600 seconds.
My windows clients, and even an ipad-mini behave nicely, asking for
DHCP renewals once ever five minutes, or at about 80% of the default
lease time, a behavior I can understand. However, several of my
guests, with their own iPads, I-watches, iPhones, connect to my
network (via a wireless access point which does not do routing
functions) and they're renewing once every 20-30 seconds. In
addition, these devices also loose connectivity for brief intervals,
which seems to be roughly synchronized with dhcp renewal. This last
fact I deduce by doing "tail -f /etc/log/messages" and hearing them
say "lost connection" at just about the same moment the DHCPREQUEST
and DHCPACK statements show up.
It's difficult to believe that Apple IOS devices (all of which are
running apple's latest) have a dhcp client problem not shared by
windows or even linux hosts.
Does anyone have any clues?
David Kurn
San Francisco
DHCPD.CONF file is excerpted below:
----------------------------------------
ddns-update-style none;
subnet 192.168.155.0 netmask 255.255.255.0 {
authoritative;
option routers 192.168.155.2;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.155.255;
option domain-name "daku.org";
option domain-name-servers 192.168.155.2;
option netbios-name-servers 192.168.155.2;
option time-offset -28800; # Pacific standard time
range dynamic-bootp 192.168.155.200 192.168.155.254;
default-lease-time 1800;
max-lease-time 3600;
}
--------------------------------------------
On 16/02/16 16:59, david wrote:> Folks > > This might be the wrong place to ask, but I don't know where to turn. > My internal home network, including wireless, is controlled by a > Centos6 server, which provides dhcpd services, along with NAT. I have > DHCPD configured with the addresses 192.168.155.200 through > 192.168.155.254 as the range for dynamic allocations. The > default-lease time is 1800 seconds, the maximum is 3600 seconds. > > My windows clients, and even an ipad-mini behave nicely, asking for > DHCP renewals once ever five minutes, or at about 80% of the default > lease time, a behavior I can understand. However, several of my > guests, with their own iPads, I-watches, iPhones, connect to my > network (via a wireless access point which does not do routing > functions) and they're renewing once every 20-30 seconds. In > addition, these devices also loose connectivity for brief intervals, > which seems to be roughly synchronized with dhcp renewal. This last > fact I deduce by doing "tail -f /etc/log/messages" and hearing them > say "lost connection" at just about the same moment the DHCPREQUEST > and DHCPACK statements show up. > > It's difficult to believe that Apple IOS devices (all of which are > running apple's latest) have a dhcp client problem not shared by > windows or even linux hosts. > > Does anyone have any clues? >does your dhcpd update the dns? name resolution for devices seems to be required for some applications and thus the dns needs to know about the leases. Have you checked your dhcpd log entries and your dns log entries? I have had situations where the dhcpd lease is dropped due to not being able to complete dns update of the info - thus the client retries again and again - they do get onto the internet but the connection drops and a new lease is requested, HTH> David Kurn > San Francisco > > DHCPD.CONF file is excerpted below: > > ---------------------------------------- > ddns-update-style none; > > subnet 192.168.155.0 netmask 255.255.255.0 { > authoritative; > option routers 192.168.155.2; > option subnet-mask 255.255.255.0; > option broadcast-address 192.168.155.255; > option domain-name "daku.org"; > option domain-name-servers 192.168.155.2; > option netbios-name-servers 192.168.155.2; > > option time-offset -28800; # Pacific standard time > > range dynamic-bootp 192.168.155.200 192.168.155.254; > default-lease-time 1800; > max-lease-time 3600; > } > > -------------------------------------------- > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos
Rob DNS service for my clients is provided by my gateway server, the same machine as the DHCPD server. I think that's what the "option domain-name-servers" line does. This allows me to provide 192.168 addresses to them when they try to access anything inside the house with a name. If it's not a locally defined name, BIND forwards the request to the internet. I'm not sure I understand about dhcpd log and dns log. I scan /var/log/messages, using the service name as the key. Looking at 'named' entries, all I see are messages of the form "clients-per-query increased to XX". I'm still mystified by the fact that only the i-devices (iphone, ipad) exhibit this behavior of rapid dhcpd renewals. Mac's and PC's don't. David At 06:48 AM 2/17/2016, you wrote:>On 16/02/16 16:59, david wrote: >>Folks >> >>This might be the wrong place to ask, but I don't know where to turn. >>My internal home network, including wireless, is controlled by a >>Centos6 server, which provides dhcpd services, along with NAT. I >>have DHCPD configured with the addresses 192.168.155.200 through >>192.168.155.254 as the range for dynamic allocations. The >>default-lease time is 1800 seconds, the maximum is 3600 seconds. >> >>My windows clients, and even an ipad-mini behave nicely, asking for >>DHCP renewals once ever five minutes, or at about 80% of the >>default lease time, a behavior I can understand. However, several >>of my guests, with their own iPads, I-watches, iPhones, connect to >>my network (via a wireless access point which does not do routing >>functions) and they're renewing once every 20-30 seconds. In >>addition, these devices also loose connectivity for brief >>intervals, which seems to be roughly synchronized with dhcp >>renewal. This last fact I deduce by doing "tail -f >>/etc/log/messages" and hearing them say "lost connection" at just >>about the same moment the DHCPREQUEST and DHCPACK statements show up. >> >>It's difficult to believe that Apple IOS devices (all of which are >>running apple's latest) have a dhcp client problem not shared by >>windows or even linux hosts. >> >>Does anyone have any clues? >does your dhcpd update the dns? name resolution for devices seems to >be required for some applications and thus the dns needs to know >about the leases. Have you checked your dhcpd log entries and your >dns log entries? I have had situations where the dhcpd lease is >dropped due to not being able to complete dns update of the info - >thus the client retries again and again - they do get onto the >internet but the connection drops and a new lease is requested, >HTH >>David Kurn >>San Francisco >> >>DHCPD.CONF file is excerpted below: >> >>---------------------------------------- >>ddns-update-style none; >> >>subnet 192.168.155.0 netmask 255.255.255.0 { >> authoritative; >> option routers 192.168.155.2; >> option subnet-mask 255.255.255.0; >> option broadcast-address 192.168.155.255; >> option domain-name "daku.org"; >> option domain-name-servers 192.168.155.2; >> option netbios-name-servers 192.168.155.2; >> >> option time-offset -28800; # Pacific standard time >> >> range dynamic-bootp 192.168.155.200 192.168.155.254; >> default-lease-time 1800; >> max-lease-time 3600; >>} >> >>--------------------------------------------
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