Posted: Sat Jan 25, 2014 16:25 Post subject: [Solved] Frequent Internet Disconnects
Device information:
TP-Link WDR4900 V1
DD-WRT v24-sp2 (01/10/14) std - build 23320
Linux 3.10.26 #123 Fri Jan 10 07:45:59 CET 2014 ppc
My WAN link drops every 40-50 minutes for no reason. These reconnects cannot be traced back to my ISP.
I'm connecting via DHCP and not using any VPN at all.
Here is what happens in /var/log/messages:
Code:
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : vpn modules successfully unloaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_conntrack_proto_gre successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_nat_proto_gre successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_conntrack_pptp successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_nat_pptp successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: process_monitor : Process Monitor successfully stopped
Jan 23 21:44:13 ddwrt user.info syslog: process_monitor successfully started
Jan 23 21:44:13 ddwrt daemon.debug process_monitor[8403]: We need to re-update after 3600 seconds
Jan 23 21:44:13 ddwrt daemon.info process_monitor[8403]: set timer: 3600 seconds, callback: ntp_main()
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : vpn modules successfully unloaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_conntrack_proto_gre successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_nat_proto_gre successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_conntrack_pptp successfully loaded
Jan 23 21:44:13 ddwrt user.info syslog: vpn modules : nf_nat_pptp successfully loaded
Jan 23 21:44:14 ddwrt user.info syslog: wland : WLAN daemon successfully stopped
Jan 23 21:44:14 ddwrt user.info syslog: vpn modules : vpn modules successfully unloaded
Jan 23 21:44:14 ddwrt user.info syslog: vpn modules : nf_conntrack_proto_gre successfully loaded
Jan 23 21:44:14 ddwrt user.info syslog: vpn modules : nf_nat_proto_gre successfully loaded
Jan 23 21:44:14 ddwrt user.info syslog: vpn modules : nf_conntrack_pptp successfully loaded
Jan 23 21:44:14 ddwrt user.info syslog: vpn modules : nf_nat_pptp successfully loaded
Jan 23 21:44:14 ddwrt user.info syslog: wland : WLAN daemon successfully started
Jan 23 21:44:14 ddwrt user.info syslog: WAN is up. IP: 77.22.xxx.xxx
But why does it happen? There has to be a trigger.
What could be the reason for this?
Last edited by renkforce on Mon Jan 27, 2014 9:55; edited 1 time in total
Yes, I isolated the problem to the dd-wrt router.
Its verified by connecting the PC directly to the cable modem. Also there are no more interruptions if I use another router or the stock firmware from TP-Link instead of dd-wrt.
Finally I was able to determine and solve the problem.
After I added a firewall exception allowing inbound DHCP traffic, my connection still dropped after exactly 45 minutes.
Then I decided to handle the lease by myself and was able to renew the DHCP lease right before the drop would normally occur. This prevents the WAN disconnect/reconnect.
Code:
kill -USR1 `cat /var/run/udhcpc.pid` 2> /dev/null
To make this permanent, I created a crob job under Administration -> Management to renew the lease every 20 minutes. You should pick an interval less than half your lease time.
Finally I was able to determine and solve the problem.
After I added a firewall exception allowing inbound DHCP traffic, my connection still dropped after exactly 45 minutes.
Then I decided to handle the lease by myself and was able to renew the DHCP lease right before the drop would normally occur. This prevents the WAN disconnect/reconnect.
Code:
kill -USR1 `cat /var/run/udhcpc.pid` 2> /dev/null
To make this permanent, I created a crob job under Administration -> Management to renew the lease every 20 minutes. You should pick an interval less than half your lease time.