Posted: Thu Mar 31, 2011 1:49 Post subject: ASUS RT-N16 drops every 5 mins on WAN DHCP lease time
Hi,
Today, I switch my ISP to another company, and my WAN setting switches from PPPoE to Automatic Configuration - DHCP. Somehow the router gives me a lease time of 5 mins. Every 5 mins, my internet connection will drop. I call the ISP, and they told me that this should be a problem of the router. The 5 mins lease time is normal, and the connection won't drop. Does anybody experience this problem?
My WAN setting,
Automatic Configuration - DHCP
STP disable
Joined: 31 Jul 2009 Posts: 492 Location: Toronto, ON, CA
Posted: Thu Mar 31, 2011 3:32 Post subject:
Log in to the router and go to Administration>Commands Tab. Copy and paste the following code into the Command Shell text box. Press Save Firewall and reboot after a minute. This should resolve your issue.
Joined: 31 Jul 2009 Posts: 492 Location: Toronto, ON, CA
Posted: Thu Mar 31, 2011 13:18 Post subject:
This is known bug where the firewall blocks DHCP renewal requests on WAN causing disconnects on renewal. There is a bug ticket that was created a long time ago but was never fixed.
bbmak wrote:
Thank you so much.
Do you know why this problem occur? Did Eko release any built that fixes such problem?
_________________ Asus RT-N16 [Build King Kong 18050M NEWD-2 K2.6 + Optware + My Page]
Also, it looks like it's allowing traffic from packets with a source port 67 to port 68... which is DHCP.
That means for some reason your firewall is blocking DHCP SYN/ACKs basically.
What build of DD-WRT are you running? I have build 16214 Mega and I leave it on automatic configuration for WAN and I definitely turn on my firewall.
I also have the RT-N16 router.
deltatux
I am using Sonic.net. I call the support. The support said that 5 mins lease time is normal. It won't drop. The problem may be on your router.
Using Eko Mini built 3/10/2011
This is known bug where the firewall blocks DHCP renewal requests on WAN causing disconnects on renewal. There is a bug ticket that was created a long time ago but was never fixed.
bbmak wrote:
Thank you so much.
Do you know why this problem occur? Did Eko release any built that fixes such problem?
Also, it looks like it's allowing traffic from packets with a source port 67 to port 68... which is DHCP.
That means for some reason your firewall is blocking DHCP SYN/ACKs basically.
What build of DD-WRT are you running? I have build 16214 Mega and I leave it on automatic configuration for WAN and I definitely turn on my firewall.
I also have the RT-N16 router.
deltatux
I am using Sonic.net. I call the support. The support said that 5 mins lease time is normal. It won't drop. The problem may be on your router.
Using Eko Mini built 3/10/2011
No there is not any build that fixes it so don't waste your time. The firewall scripts works fine. The problem is really with half-bridge modems that assign the router a public IP but send DHCP from their private LAN IP which is outside of the WAN subnet. The firewall prevents the lease from being renewed since the replies are coming from a different subnet than the WAN IP is in. After the lease expires, the WAN IP is lost, and the firewall no longer cares where the new DHCP lease comes from.
http://svn.dd-wrt.com/ticket/973 _________________ Read the forum announcements thoroughly! Be cautious if you're inexperienced.
Available for paid consulting. (Don't PM about complicated setups otherwise)
Looking for bricks and spare routers to expand my collection. (not interested in G spec models)
Joined: 04 Feb 2007 Posts: 426 Location: Fountain of Youth
Posted: Thu Mar 31, 2011 21:36 Post subject: DD-WRT v24-sp2 (11/21/10) big on ASUS RT-N16
DD-WRT v24-sp2 (11/21/10) big (SVN revision 15778) connected to WAN via DHCP is working fine. IMHO a 5 minute lease time is unreasonably short within the context.
or just enter this code without deactivating firewall will be enough?
And I must enter this command after every router reboot (from GUI or by unplugging power cable) or it will stay in it for ever?
or just enter this code without deactivating firewall will be enough?
And I must enter this command after every router reboot (from GUI or by unplugging power cable) or it will stay in it for ever?
You do not need to change firewall settings. The following commands will simply instruct router firewall to allow DHCP renewals to go through and once you save the firewall rule by following the provided instructions, you should not need to do this again unless your reset your router to setting defaults or upgrade firmware. Log in to the router and go to Administration>Commands Tab. Copy and paste the following code into the Command Shell text box. Press Save Firewall and reboot after a minute. This should resolve your issue.
I do that you said:
[img]http://img.leprosorium.com/1157266[/img]
Started online radio and EVE Online client, press "DHCP Release" - router droped DCHP, all is okay - radio playing and connection to the EVE-server is stable. But after I pressed "DHCP Renew" radio stops and EVE client crashes because connection to the server was lost.
Joined: 31 Jul 2009 Posts: 492 Location: Toronto, ON, CA
Posted: Fri Jun 10, 2011 15:49 Post subject:
Venique wrote:
I do that you said:
[img]http://img.leprosorium.com/1157266[/img]
Started online radio and EVE Online client, press "DHCP Release" - router droped DCHP, all is okay - radio playing and connection to the EVE-server is stable. But after I pressed "DHCP Renew" radio stops and EVE client crashes because connection to the server was lost.
Why are you releasing or renewing DHCP manually? DHCP will auto renew when lease expires. _________________ Asus RT-N16 [Build King Kong 18050M NEWD-2 K2.6 + Optware + My Page]