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ssh_exchange_identification issue

Discussion in 'Web and Network Services' started by CanOfBees, Oct 1, 2013.

  1. CanOfBees

    CanOfBees New Member

    Messages:
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    Hi all,

    I've posted to the PC-BSD forums but haven't heard anything yet [1]. I know there could be some differences, but there's significantly higher traffic here and I'm hoping someone will be able to shed some light on my problem.

    I'm using 9.2;
    Code:
    > uname -a
    FreeBSD rook 9.2-RELEASE-p7 FreeBSD 9.2-RELEASE-p7 #0: Wed Sep 11 15:02:50 UTC 2013     root@amd64-builder.pcbsd.org:/usr/obj/usr/src/sys/GENERIC  amd64
    When I'm in my office and connected to our network via ethernet (em0) I am unable to ssh into my workstation from my laptop. I get the following error:

    Code:
    > ssh workstation.at.the.office
    ssh_exchange_identification: Connection closed by remote host
    I'm able to ssh into every other machine that I typically access. I've checked the /etc/hosts.allow and /etc/hosts.deniedssh, but as far as I can tell everything looks normal. /etc/hosts.allow has the following:
    Code:
    sshd : /etc/hosts.deniedssh : deny 
    sshd : ALL : allow 
    and /etc/hosts.deniedssh is empty.

    The crowning weirdness is that if I unplug the ethernet cable and use the wireless network, I can ssh into my workstation without problems (except for the horribly slow network). I have lagg0 enabled, so maybe the problem is there but I'm not sure.

    I've attached the output of ifconfig [2]. Please let me know if there's anything else I can provide to help clear this up. Thanks in advance for your time and trouble.

    [1] http://forums.pcbsd.org/showthread.php?p=109758#post109758
    [2] ifconfig
    Code:
    > ifconfig
    em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
    	options=4219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC,VLAN_HWTSO>
    	ether 00:1d:72:98:56:41
    	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
    	media: Ethernet autoselect (100baseTX <full-duplex>)
    	status: active
    iwn0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 2290
    	ether 00:1d:72:98:56:41
    	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
    	media: IEEE 802.11 Wireless Ethernet autoselect mode 11ng
    	status: associated
    ipfw0: flags=8801<UP,SIMPLEX,MULTICAST> metric 0 mtu 65536
    	nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
    lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
    	options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
    	inet6 ::1 prefixlen 128 
    	inet6 fe80::1%lo0 prefixlen 64 scopeid 0xa 
    	inet 127.0.0.1 netmask 0xff000000 
    	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
    lagg0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
    	ether 00:1d:72:98:56:41
    	inet6 fe80::21d:72ff:fe98:5641%lagg0 prefixlen 64 scopeid 0xb 
    	inet 160.36.193.175 netmask 0xfffffc00 broadcast 160.36.195.255
    	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
    	media: Ethernet autoselect
    	status: active
    	laggproto failover lagghash l2,l3,l4
    	laggport: wlan0 flags=0<>
    	laggport: em0 flags=5<MASTER,ACTIVE>
    wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
    	ether 00:1d:72:98:56:41
    	inet6 fe80::21d:72ff:fe98:5641%wlan0 prefixlen 64 scopeid 0xc 
    	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
    	media: IEEE 802.11 Wireless Ethernet OFDM/36Mbps mode 11ng
    	status: associated
    	ssid office-open channel 11 (2462 MHz 11g ht/20) bssid 6c:f3:7f:ad:ea:61
    	country US authmode OPEN privacy OFF txpower 14 bmiss 10
    	scanvalid 450 bgscan bgscanintvl 300 bgscanidle 250 roam:rssi 7
    	roam:rate 64 protmode CTS ampdulimit 64k ampdudensity 8
    	-amsdutx amsdurx shortgi wme roaming MANUAL
     
  2. SirDice

    SirDice Moderator Staff Member Moderator

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    Are there any Match Address entries in the hosts /etc/ssh/sshd_config?
     
  3. CanOfBees

    CanOfBees New Member

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    @SirDice,

    I'm not seeing any.
    # cat /etc/ssh/sshd_config | grep Match
    Code:
    #Match User anoncvs
    It's the same on both machines.
    Thanks!
     
    Last edited by a moderator: Oct 16, 2014