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Thread: headless server "froze" seems like it's simply ignoreing dhcp offers?

  1. #1
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    headless server "froze" seems like it's simply ignoreing dhcp offers?

    Okay so I have a very, very, very humble home server that I use for mumble, I got the bright idea to try using it as a minecraft server, just to see if it could handle the load, there would only be a max of like 3 clients at one time ever. I started it up and started playing, I kept htop open to see how it handled the load, after a few minutes everything just froze up and I couldn't contact the server via ping or ssh. With just me playing the cpu was around 80% and ram around 90% used.

    Checking syslog (that's the right log to check yes?) I notice the same day that this happened syslog is spammed with what seems like very rapid dhcp traffic that is just, getting ignored. Here is what I am talking about. Could that be a symptom of the system being overloaded? Or something else entirely?

    Code:
    Apr 18 14:31:53  dhclient: last message repeated 5 times
    Apr 18 14:32:42  dhclient: last message repeated 3 times
    Apr 18 14:32:42 voiceserv kernel: [1126699.590590] [UFW BLOCK] IN=eth0 OUT= MAC=01:00:5e:00:00:01:64:0f:28:8d:28:41:08:00 SRC=192.168.1.254 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0xC0 TTL=1 ID=30
    842 PROTO=2 
    Apr 18 14:32:48 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 192.168.1.254 port 67
    Apr 18 14:33:04 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 192.168.1.254 port 67
    Apr 18 14:33:23 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:34:27  dhclient: last message repeated 5 times
    Apr 18 14:34:33 voiceserv avahi-daemon[714]: Withdrawing address record for 108.215.132.8 on eth0.
    Apr 18 14:34:33 voiceserv avahi-daemon[714]: Leaving mDNS multicast group on interface eth0.IPv4 with address 108.215.132.8.
    Apr 18 14:34:33 voiceserv avahi-daemon[714]: Interface eth0.IPv4 no longer relevant for mDNS.
    Apr 18 14:34:33 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:34:33 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:34:33 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:34:56  dhclient: last message repeated 2 times
    Apr 18 14:34:56 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:34:56 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:34:56 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:34:59 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:35:07 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:35:07 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:35:07 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:35:10 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:35:18 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:35:18 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:35:18 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:35:35  dhclient: last message repeated 2 times
    Apr 18 14:35:35 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:35:35 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:35:35 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:35:46  dhclient: last message repeated 2 times
    Apr 18 14:35:46 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:35:46 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:35:46 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:36:02  dhclient: last message repeated 2 times
    Apr 18 14:36:02 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:36:02 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:36:02 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:36:05 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:36:13 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:36:13 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:36:13 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:36:34  dhclient: last message repeated 2 times
    Apr 18 14:36:34 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:36:34 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:36:34 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:36:58  dhclient: last message repeated 2 times
    Apr 18 14:36:58 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    Apr 18 14:36:58 voiceserv dhclient: DHCPOFFER of 108.215.132.8 from 192.168.1.254
    Apr 18 14:36:58 voiceserv dhclient: DHCPREQUEST of 108.215.132.8 on eth0 to 255.255.255.255 port 67
    Apr 18 14:37:10  dhclient: last message repeated 2 times
    Apr 18 14:37:10 voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
    "You can't expect to hold supreme executive power just because some watery tart lobbed a sword at you"

    "Don't let your mind wander -- it's too little to be let out alone."

  2. #2
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    Huh, it shouldn't randomly lose it's IP.

    What happens if you set it to a static ip and reboot?
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  3. #3
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    Quote Originally Posted by CharlesA View Post
    Huh, it shouldn't randomly lose it's IP.

    What happens if you set it to a static ip and reboot?
    Unfortunately I can't. This is a dynamically allocated ip address. It's actually behind a router, when that router puts a device in DMZ+ mode it assigns the device it's [the routers] dynamic public ip. Since that is due to change I can't simply assign it statically.
    "You can't expect to hold supreme executive power just because some watery tart lobbed a sword at you"

    "Don't let your mind wander -- it's too little to be let out alone."

  4. #4
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    If you have console access when this happens, have you tried killing and restarting the dhclient?
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  5. #5
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    Okay so, I hooked up a monitor and keyboard, as soon as I start the minecraft server my connection just *poofs*, If I manually run dhclient it just quits and logs no broadcast interfaces found to syslog. Upon a reboot the boot process hangs for about a minute on "waiting for network configuration" and has the exact same symptoms. It doesn't work until I shut it down and wait for a very good while to boot it back up.

    the log specifically looks like

    Code:
    *timestamp* voiceserv dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
    *timestamp* voiceserv dhclient: No broadcast interfaces found - exiting.
    If I staticly set the ip to something that should be on my lan (192.168.1.3, which is reserved for static) it won't respond to ping or ssh attempts.

    --------------

    I got the bright idea to reboot the switch it's connected to, and everything is working for now. It's just strange that twice the switch essentially died just as I started the minecraft server, and my network printer was working which is also connected to the same switch.

    For now I'm attributing this as a switch failure, thanks for the help and feel free to offer any insight (even it if's a Yup, you need a new switch)



    Yikes I don't know if this little guy can keep up, we'll see.
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    "You can't expect to hold supreme executive power just because some watery tart lobbed a sword at you"

    "Don't let your mind wander -- it's too little to be let out alone."

  6. #6
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    Wow. I wonder if the switch was the problem. How old is it?

    I'd do more testing before replacing it unless it's a fairly old one.
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  7. #7
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    Quote Originally Posted by CharlesA View Post
    Wow. I wonder if the switch was the problem. How old is it?

    I'd do more testing before replacing it unless it's a fairly old one.
    I got it [the switch] second hand at a goodwill at least 5 years ago. The computer itself is older than that [read, it originally had win95 on it], I'll do more fiddling with it in a few days, try running it under that load directly connected to the router I guess. I don't know what else I can do to test it.
    "You can't expect to hold supreme executive power just because some watery tart lobbed a sword at you"

    "Don't let your mind wander -- it's too little to be let out alone."

  8. #8
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    Hi Jerome

    attributing this as a switch failure
    Switch problems are more common than you might imagine, especially if you have a cheap one.

    I've had experience of many aging rather badly and jamming up networks, which I presume to be degradation of the eletrical properties. Also many switches behave poorly when given bursts of heavy load, especially broadcasts, or having to learn many ether addresses; which I've surmised is they behave badly when they run out of RAM for incoming frames or outgoing queues.

    Debug by replacing with a known-good direct cable or another switch or hub. Remember that older computers don't have "auto-swap" so you'll probably need an ethernet swap cable if you do it directly.

    Hope that helps.

    Kind regards,
    Jonathan.

  9. #9
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    Re: headless server "froze" seems like it's simply ignoreing dhcp offers?

    How about just dropping requests to the broadcast address with iptables?

    Code:
    sudo iptables -I INPUT -i eth0 -d 255.255.255.255 -j DROP

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