Date: Wed, 20 Feb 2013 11:00:24 +0100 From: Fleuriot Damien <ml@my.gd> To: mexas@bristol.ac.uk Cc: freebsd-questions@freebsd.org Subject: Re: cannot ssh into a box with DHCP assigned IP address Message-ID: <9A8F9CCD-C90B-4033-992F-0458D6128005@my.gd> In-Reply-To: <201302200945.r1K9jpq7029535@mech-cluster241.men.bris.ac.uk> References: <201302200945.r1K9jpq7029535@mech-cluster241.men.bris.ac.uk>
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On Feb 20, 2013, at 10:45 AM, Anton Shterenlikht <mexas@bristol.ac.uk> = wrote: > From: Fleuriot Damien <ml@my.gd> > To: mexas@bristol.ac.uk > Subject: Re: cannot ssh into a box with DHCP assigned IP address > Date: Wed, 20 Feb 2013 10:31:22 +0100 > Cc: freebsd-questions@freebsd.org >=20 > On Feb 20, 2013, at 10:28 AM, Anton Shterenlikht = <mexas@bristol.ac.uk> wrote: >=20 > > I have a laptop with FreeBSD -current, > > with ip address assigned via DHCP. > > The laptop has neither a static ip address, > > nor a domain. > >=20 > > I can ping the laptop fine, but cannot > > ssh into it. The sshd is running, /etc/ssh/ssd_config > > seems fine, /etc/hosts.allow is fine. > > However, /etc/hosts is just the default: > >=20 > > # > > ::1 localhost localhost.my.domain > > 127.0.0.1 localhost localhost.my.domain > > # > >=20 > > Is it the lack of a domain that prevents > > me from getting ssh access? > > I try to ssh with just a dynamic ip address, > > for which ping seems to work fine. > > Or is the problem somewhere else? > >=20 > > I'm not even sure I'm asking the right > > questions. > >=20 > > Thanks > >=20 > > Anton >=20 >=20 > First, check what ports SSH listens on: > sockstat | grep ssh >=20 > root@zzz:~ # sockstat | grep ssh > mexas ssh 16193 3 tcp4 172.21.220.12:20541 = 137.222.187.241:22 > root sshd 1091 3 tcp6 *:22 *:* > root sshd 1091 4 tcp4 *:22 *:* > root@zzz:~ # >=20 > I also see: >=20 > /var/log/auth.log:Feb 18 11:54:25 zzz sshd[1091]: Server listening on = :: port 22 > . > /var/log/auth.log:Feb 18 11:54:25 zzz sshd[1091]: Server listening on = 0.0.0.0 po > rt 22. >=20 > Is 0.0.0.0 expected? >=20 0.0.0.0 =3D * =3D all IPs / interfaces > Anything else I should check in the logs? >=20 Not that I'm aware of >=20 > Then, assuming SSH indeed listens on *:22 , > check if you have a firewall running that > could be preventing packets from reaching your box. >=20 > I don't think so. > There's nothing in the kernel config >=20 > By the way, do you get a login prompt at all, > over SSH, or just a plain timeout or connection reset ? >=20 > Just a timeout: >=20 > root@zzz:~ # ifconfig wlan0 > wlan0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 = mtu 1500 > ether 00:21:5c:50:68:c3 > inet 172.21.220.12 netmask 0xfffffc00 broadcast 255.255.255.255 > nd6 options=3D29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> > media: IEEE 802.11 Wireless Ethernet OFDM/54Mbps mode 11g > status: associated > ssid eduroam channel 1 (2412 MHz 11g) bssid 00:3a:98:62:cd:a0 > country US authmode WPA2/802.11i privacy ON deftxkey UNDEF > AES-CCM 2:128-bit AES-CCM 3:128-bit txpower 14 bmiss 10 = scanvalid 450 > bgscan bgscanintvl 300 bgscanidle 250 roam:rssi 7 roam:rate 5 > protmode CTS wme roaming MANUAL > root@zzz:~ # >=20 > TZAV> ping 172.21.220.12 > PING 172.21.220.12 (172.21.220.12): 56 data bytes > 64 bytes from 172.21.220.12: icmp_seq=3D0 ttl=3D60 time=3D2.056 ms > 64 bytes from 172.21.220.12: icmp_seq=3D1 ttl=3D60 time=3D1.766 ms > ^C >=20 > TZAV> ssh 172.21.220.12 > ssh: connect to host 172.21.220.12 port 22: Operation timed out > TZAV> >=20 > Thanks >=20 > Anton >=20 Run this on your server: tcpdump -ni wlan0 ip and port 22 Then try to ssh to the box, see if SYN packets arrive, see if your box = sends SYN/ACK back.
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