On Mon, Apr 6, 2015 at 12:15 PM, Anton Farber <dr_sweety_1...@hotmail.com> wrote: > Good evening, > > I've opened a thread on the FreeBSD networking forum > (https://forums.freebsd.org/threads/jail-fails-to-connect-to-main-host.50833/) > as sometime ago my FreeBSD server (initially running 10.1, now CURRENT) > started to behave strangely after an upgrade from 10.0 to 10.1. I first > noticed that a jail (192.168.1.5) wasn't able to contact the base system > (192.168.1.1). Running a tcpdump revealed the following: the jail is using > em0 instead of lo0 for communicating with the base system:
You need to look at your routing tables. From inside the jail, run "netstat -rn -f inet". You probably won't see any entry for 127.0.0.1 or 127.0.0.0/8. Those are the entries that your jail needs in order to talk to the base system. You can add them, but think carefully. Many server processes, such as ntpd, have reduced security for connections coming over 127.0.0.1. Whether or not it is appropriate to add those routes depends on why you are using a jail. -Alan > > ------------------------ > * tcpdump on em0 > Source Destination Protocol Length Info > 192.168.1.5 192.168.1.1 TCP 74 28848→22 [SYN] > * tcpdump on lo0 > Source Destination Protocol Length Info > 192.168.1.1 192.168.1.5 TCP 64 22→28848 [SYN, ACK] > ------------------------ > > I don't think that this is the way it's supposed to work. Next thing was, > that random hosts on the network were unable to contact the server. The > server on the other hand thought it needed to reach those hosts (in this > example 192.168.1.61) via the router: > > ------------------------ > # ping -c 1 192.168.1.61 > PING 192.168.1.61 (192.168.1.61): 56 data bytes > 36 bytes from router.local.lan (192.168.1.254): Redirect Host(New addr: > 192.168.1.61) > Vr HL TOS Len ID Flg off TTL Pro cks Src Dst > 4 5 00 0054 a734 0 0000 40 01 4fe6 192.168.1.1 192.168.1.61 > > 64 bytes from 192.168.1.61: icmp_seq=0 ttl=64 time=1.009 ms > > --- 192.168.1.61 ping statistics --- > 1 packets transmitted, 1 packets received, 0.0% packet loss > round-trip min/avg/max/stddev = 1.009/1.009/1.009/0.000 ms# > ------------------------ > > Other hosts on the same network were able to reach 192.168.1.61 directly, so > it can't be neither 192.168.1.61 nor the router (I do not have any static > routes for 192.168.1.61/32 on my router) that are causing the problems. > Status on the server: > > ------------------------ > # arp -a > server.local.Lan (192.168.1.1) at 00:1c:c0:6f:c2:60 on em0 permanent > [ethernet] > laptop.local.Lan (192.168.1.32) at 5c:26:0a:2a:37:10 on em0 expires in 1197 > seconds [ethernet] > jail.local.Lan (192.168.1.5) at 00:1c:c0:6f:c2:60 on em0 permanent [ethernet] > WinXP.local.Lan (192.168.1.4) at 08:00:27:80:b8:10 on em0 expires in 1200 > seconds [ethernet] > ? (192.168.1.61) at 00:04:20:05:31:38 on em0 expires in 1150 seconds > [ethernet] > ? (192.168.1.255) at (incomplete) on em0 expired [ethernet] > Router.local.Lan (192.168.1.254) at 00:0d:b9:00:11:68 on em0 expires in 1150 > seconds [ethernet] > Phone.local.Lan (192.168.1.21) at 00:0e:08:bc:ed:94 on em0 expires in 799 > seconds [ethernet] > # netstat -rn > Routing tables > > Internet: > Destination Gateway Flags Netif Expire > default 192.168.1.254 UGS em0 > 127.0.0.1 link#2 UH lo0 > 192.168.1.0/24 link#1 U em0 > 192.168.1.1 link#1 UHS lo0 > 192.168.1.5 link#1 UHS lo0 > 192.168.1.5/32 link#1 U em0 > > Internet6: > Destination Gateway Flags > Netif Expire > ::/96 ::1 UGRS lo0 > ::1 link#2 UH lo0 > ::ffff:0.0.0.0/96 ::1 UGRS lo0 > fe80::/10 ::1 UGRS lo0 > fe80::%lo0/64 link#2 U lo0 > fe80::1%lo0 link#2 UHS lo0 > fe80::%tun0/64 link#4 U tun0 > fe80::21c:c0ff:fe6f:c260%tun0 link#4 UHS lo0 > ff02::/16 ::1 UGRS lo0 > ------------------------ > > So the server knew the (correct) MAC address of .61 but still tried to reach > it via the router. I've run a tcpdump on em0, this is where things get > interesting: > > ------------------------ > No. Time Source Destination Protocol Length Info > 186 1.028186 192.168.1.1 192.168.1.61 ICMP 98 Echo (ping) request > id=0x2220, seq=0/0, ttl=64 (reply in 190) > > Ethernet II, Src: IntelCor_6f:c2:60 (00:1c:c0:6f:c2:60), Dst: > PcEngine_00:11:68 (00:0d:b9:00:11:68) > > No. Time Source Destination Protocol Length Info > 189 1.029008 192.168.1.254 192.168.1.1 ICMP 70 Redirect > (Redirect for host) > > Ethernet II, Src: PcEngine_00:11:68 (00:0d:b9:00:11:68), Dst: > IntelCor_6f:c2:60 (00:1c:c0:6f:c2:60) > > No. Time Source Destination Protocol Length Info > 190 1.029392 192.168.1.61 192.168.1.1 ICMP 98 Echo (ping) reply > id=0x2220, seq=0/0, ttl=64 (request in 186) > > Ethernet II, Src: SlimDevi_05:31:38 (00:04:20:05:31:38), Dst: > IntelCor_6f:c2:60 (00:1c:c0:6f:c2:60) > ------------------------ > > The server issues an echo request for .61 but is using the router's MAC > address (:68)! Obviously the router answers with a redirect.. > > I've shut down all daemons and kernel modules if possible until just the > absolute bare minimum (sshd, init and some other base services) was running. > I've upgraded to CURRENT. This didn't change anything. What helped in the end > was issuing a "route flush ; route add default 192.168.1.254": the server was > immediately able to contact .61 directly. > > The problem seemingly appears randomly, sometimes it takes weeks for it to > reappear. > > Sorry for the long post, I've tried to keep it as compact as possible. Does > anyone have any idea what might be causing those problems? > > Regards, Anton > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
