WAN DHCP issue after link down+ link up
Posted: Fri Aug 23, 2013 8:36 pm
I changed my ISP to cable modem in this week.
my WAN use DHCP to get a IP form WAN.
I find the WAN is unstable, it may link down once a day.
after link down then link up in WAN, I can't access internet except my router issue DHCP renew request. I use this way manually to fixed it.
Can udhcpc reissue DHCP renew request after Link down+ Link up?
does it possible to update /lib/netifd/dhcp.script to support this feature?
I also do some test by my slef as below.
Test 1: remove the WAN cable then plug-in
In this test, remove WAN cable causes link down, after I plug-in the WAN cable then Link up.
the internet access is ok after link up. no need DHCP renew request.
I think this is correct behavior of my router and cable modem.
Test 2: power off then power on the cable modem
in this test, the WAN is also link down then link up in my router.
use "ip addr" show my WAN is Link up
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc hfsc state UP qlen 1000
link/ether 90:f6:52:b7:47:2d brd ff:ff:ff:ff:ff:ff
inet 213.121.241.48/24 brd 213.121.241.255 scope global eth1
but I can't access internet.
I think this issue is the cable modem had lost DHCP information after power off.
Then I can manually send dhcp renew request to make the WAN can access internet again.
below is the log from "logread" when issue DHCP renew request
Aug 24 07:43:42 Gargoyle daemon.notice netifd: wan (7081): Performing a DHCP renew
Aug 24 07:43:46 Gargoyle daemon.notice netifd: wan (7081): Sending select for 213.121.241.48...
Aug 24 07:43:47 Gargoyle daemon.notice netifd: wan (7081): Lease of 213.121.241.48 obtained, lease time 21600
I suspect my original issue is like Test 2, my cable modem maybe have a bug then lose DHCP information, that's why I need to reissue DHCP renew request to make it work.
if the link between my router and cable modem have compatible issue then cause link down+ link up just like Test 1. it should no need DHCP renew request.
so, If I want to patch this cable modem issue(I suspect). Please help me how to do. Or you think I need to ask my ISP to fixed it?
my WAN use DHCP to get a IP form WAN.
I find the WAN is unstable, it may link down once a day.
after link down then link up in WAN, I can't access internet except my router issue DHCP renew request. I use this way manually to fixed it.
Can udhcpc reissue DHCP renew request after Link down+ Link up?
does it possible to update /lib/netifd/dhcp.script to support this feature?
I also do some test by my slef as below.
Test 1: remove the WAN cable then plug-in
In this test, remove WAN cable causes link down, after I plug-in the WAN cable then Link up.
the internet access is ok after link up. no need DHCP renew request.
I think this is correct behavior of my router and cable modem.
Test 2: power off then power on the cable modem
in this test, the WAN is also link down then link up in my router.
use "ip addr" show my WAN is Link up
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc hfsc state UP qlen 1000
link/ether 90:f6:52:b7:47:2d brd ff:ff:ff:ff:ff:ff
inet 213.121.241.48/24 brd 213.121.241.255 scope global eth1
but I can't access internet.
I think this issue is the cable modem had lost DHCP information after power off.
Then I can manually send dhcp renew request to make the WAN can access internet again.
below is the log from "logread" when issue DHCP renew request
Aug 24 07:43:42 Gargoyle daemon.notice netifd: wan (7081): Performing a DHCP renew
Aug 24 07:43:46 Gargoyle daemon.notice netifd: wan (7081): Sending select for 213.121.241.48...
Aug 24 07:43:47 Gargoyle daemon.notice netifd: wan (7081): Lease of 213.121.241.48 obtained, lease time 21600
I suspect my original issue is like Test 2, my cable modem maybe have a bug then lose DHCP information, that's why I need to reissue DHCP renew request to make it work.
if the link between my router and cable modem have compatible issue then cause link down+ link up just like Test 1. it should no need DHCP renew request.
so, If I want to patch this cable modem issue(I suspect). Please help me how to do. Or you think I need to ask my ISP to fixed it?