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Author Topic: WAN dhcp (dhclient) going to wrong IP  (Read 1240 times)

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Offline bri189

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WAN dhcp (dhclient) going to wrong IP
« on: July 27, 2016, 05:52:51 pm »
Occassionally my WAN drops (don't know why, not important right now), if dhclient is doing job correctly though it should renew lease with ISP and be seamless.

Instead what is happening is it is trying to renew with 192.168.100.1 - no idea what this is; thinking maybe the ISP 'guest wireless' that I have no control over and can't turn off.

Anyway, I have configured WAN already to reject lease from 192.168.100.1 and from logs it appears to be trying to do that, but sometimes it gives up and only way to get my true IP from ISP is to either reset the ISP modem or log into pfSense (requires being at home) and manually releasing/renewing.   Curious if something I'm blocking inbound is causing WAN address to not renew correctly as well - on old Linksys my WAN side never had these type of issue, but that's a side of the network I don't know very well.

I've now set up a floating rule to block (UDP 67/68) outbound from WAN to 192.168.100.1, but not sure this is the best way to address and not sure if pfSense still won't give up.   Is there a way I can force pfSense to just stop this from happening or is there something I might have configured wrong on WAN that I need to look at?

Relevant logs with actual IP address from ISP removed and replace with 70.1.15.15:

Quote
Jul 27 11:00:25   dhclient      ifconfig em0 inet 70.1.15.15 netmask 255.255.254.0 broadcast 255.255.255.255
Jul 27 11:00:25   dhclient      Starting add_new_address()
Jul 27 11:00:25   dhclient      TIMEOUT
Jul 27 11:00:25   dhclient   44743   Trying recorded lease 70.1.15.15
Jul 27 11:00:25   dhclient   44743   No DHCPOFFERS received.
Jul 27 11:00:18   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 11:00:18   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 7
Jul 27 11:00:05   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 11:00:05   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 13
Jul 27 10:59:54   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:54   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 11
Jul 27 10:59:43   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:43   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 11
Jul 27 10:59:33   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:33   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 10
Jul 27 10:59:29   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:29   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 4
Jul 27 10:59:27   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:27   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 2
Jul 27 10:59:25   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:25   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 2
Jul 27 10:59:24   dhclient   44743   DHCPOFFER from 192.168.100.1 rejected.
Jul 27 10:59:24   dhclient   44743   DHCPDISCOVER on em0 to 255.255.255.255 port 67 interval 1
Jul 27 10:59:15   dhclient   44743   DHCPNACK from 192.168.100.1 rejected.
Jul 27 10:59:15   dhclient   44743   DHCPREQUEST on em0 to 255.255.255.255 port 67
Jul 27 10:59:10   dhclient   44743   DHCPNACK from 192.168.100.1 rejected.
Jul 27 10:59:10   dhclient   44743   DHCPREQUEST on em0 to 255.255.255.255 port 67
Jul 27 10:59:08   dhclient   44743   DHCPNACK from 192.168.100.1 rejected.
Jul 27 10:59:08   dhclient   44743   DHCPREQUEST on em0 to 255.255.255.255 port 67
Jul 27 10:59:06   dhclient   44743   DHCPNACK from 192.168.100.1 rejected.
Jul 27 10:59:06   dhclient   44743   DHCPREQUEST on em0 to 255.255.255.255 port 67
Jul 27 10:59:06   dhclient      PREINIT
Jul 27 10:59:02   dhclient   23360   exiting.
Jul 27 10:59:02   dhclient   23360   connection closed
Jul 27 10:59:01   dhclient   56511   em0 link state up -> down
Jul 27 10:17:40   dhclient   22602   bound to 70.1.15.15 -- renewal in 92553 seconds.

Offline cmb

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Re: WAN dhcp (dhclient) going to wrong IP
« Reply #1 on: July 27, 2016, 06:03:22 pm »
192.168.100.1 is almost certainly your modem, that's the default IP they often use in those cases. If the modem loses uplink, it tries to assign you an IP to be able to communicate with it. That's not it going to any IP, that's just that your modem is replying from that IP. Problem is your modem or its connection to your provider.

Offline bri189

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Re: WAN dhcp (dhclient) going to wrong IP
« Reply #2 on: July 27, 2016, 06:38:17 pm »
Thanks.

Yeah I was able to confirm it's the ISP modem.   Popped 192.168.100.1 it into browser and there it is: "Motrolla Modem Configuration".   No login available but able to see DHCP turned on and no ability to turn it off.

So there's nothing I really can do right?

Offline cmb

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Re: WAN dhcp (dhclient) going to wrong IP
« Reply #3 on: July 27, 2016, 06:39:04 pm »
Nothing you can do.

Offline ttabbal

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Re: WAN dhcp (dhclient) going to wrong IP
« Reply #4 on: August 02, 2016, 10:17:24 am »
Is it possible to force it to retry sooner? 92553 seconds is over a day. I'm having a similar problem, and while we can blame the provider all we like, it's not going to help anything. If we can force it to retry sooner, regardless of the current lease timeout, it would likely fix it. Since a release/renew works, forcing dhclient to retry would likely get a lease from the DHCP server and everything would work fine again. I could likely hack it up with a cron job, but there should be a better way than that.