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Old 11-26-2007, 09:34 PM   #1
Earthforce_1
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Registered: Sep 2004
Location: Kitchener, Ontario Canada
Distribution: Ubuntu, Debian
Posts: 3

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Exclamation Problem with SSH and NFS


I tried to post this yesterday, but it seemed to vanish for some reason...

I am having some strange problem with both NFS and SSH connectivity. I am running a stock Debian on the server, Ubuntu/Gutsy on both clients. I did have this working at some point, but I have no idea how I broke it...
My debian/sparc NFS server seems to be installed correctly, and when I type:
My debian/sparc NFS server seems to be installed correctly, and when I type:
showmount -e on the client after restarting nfs-kernel-server on the server, the NFS mounts are shown correctly.

rpcinfo -p shows v2 portmapper, v1 status, v2-4 nfs, v1,3,4 nlockmgr, and v1-3 mountd
But when I try to mount any of the exported volumes, I get nothing but timeouts and retries on the client which eventually gives up, (15 seconds timeout, which should be more than adequate)

After the failed mount attempt, showmount -e no longer shows any mounts.

Question: How do I check that a necessary port is not blocked? If rpcinfo and showmount pass, doesn't this mean that the ports are open?

I have taken everything out of hosts.allow and hosts.deny but it does not solve the problem. I think this is some sort of security or firewall related problem, but I am out of ideas.

I am also having ssh problems with the same machine (Sparc Ultra 10) that may be related - regardless which port I use, I cannot stay connected. It gives a port 22 connection refused error. Changing ports does not help, regardless which port I select the connection is always rejected. I have set up ssh before and it worked without a hitch. Something is borked on this machine, yet I am able to ping clients from it, and connect to the internet. (I am posting this from the troublesome server in question)
 
Old 11-27-2007, 02:00 PM   #2
acid_kewpie
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both boxes should have tcpdump installed, so just run "tcpdump -vn" and then do something involving NFS, then compare the results, see if any packets are missing, or if you have resets being sent back which would suggest a firewall or lack of a server listening.
 
Old 11-28-2007, 05:35 PM   #3
Earthforce_1
LQ Newbie
 
Registered: Sep 2004
Location: Kitchener, Ontario Canada
Distribution: Ubuntu, Debian
Posts: 3

Original Poster
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I had it working briefly, then just as suddenly it stopped working when I ran a time dd if=/files/testfile of=/dev/null bs=32k test - unfortunately, rebooting the server didn't help. I noticed that I had a very back (1MBPS) wireless connnection at the time, I wonder if the crappy network bandwidth was slowing things down and preventing the server from getting jammed up somehow?

sudo mount zack:/files /files
mount.nfs: mount to NFS server 'zack' failed: timed out, retrying
mount.nfs: mount to NFS server 'zack' failed: timed out, retrying
mount.nfs: mount to NFS server 'zack' failed: timed out, retrying
mount.nfs: mount to NFS server 'zack' failed: timed out, giving up

Packet trace:
sudo tcpdump -vn -i ath0 | grep 192.168.0.101

I can see from the logs below that at first the UDP packets are ok, but then it starts complaining that UDP port 839 is unreachable. Later on it seems to recover for a bit, then dies again. Any ideas? It can't be a firewall, or it wouldn't be getting through at all.

tcpdump: listening on ath0, link-type EN10MB (Ethernet), capture size 96 bytes
18:25:54.177559 arp who-has 192.168.0.101 tell 192.168.0.67
18:25:54.179260 arp reply 192.168.0.101 is-at 00:40:f4:e8:db:6a
18:25:56.177580 IP (tos 0x0, ttl 64, id 10031, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.67.58961 > 192.168.0.101.111: S, cksum 0xf271 (correct), 620225837:620225837(0) win 5840 <mss 1460,sackOK,timestamp 18205386 0,nop,wscale 7>
18:25:56.197716 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.101.111 > 192.168.0.67.58961: S, cksum 0x5f54 (correct), 1891845502:1891845502(0) ack 620225838 win 5792 <mss 1460,sackOK,timestamp 17554419 18205386,nop,wscale 3>
18:25:56.197749 IP (tos 0x0, ttl 64, id 10032, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.58961 > 192.168.0.101.111: ., cksum 0xa489 (correct), ack 1 win 46 <nop,nop,timestamp 18205391 17554419>
18:25:56.197825 IP (tos 0x0, ttl 64, id 10033, offset 0, flags [DF], proto TCP (6), length 112) 192.168.0.67.58961 > 192.168.0.101.111: P 1:61(60) ack 1 win 46 <nop,nop,timestamp 18205391 17554419>
18:25:56.219759 IP (tos 0x0, ttl 64, id 40579, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.101.111 > 192.168.0.67.58961: ., cksum 0xa19e (correct), ack 61 win 724 <nop,nop,timestamp 17554428 18205391>
18:25:56.219861 IP (tos 0x0, ttl 64, id 40580, offset 0, flags [DF], proto TCP (6), length 84) 192.168.0.101.111 > 192.168.0.67.58961: P 1:33(32) ack 61 win 724 <nop,nop,timestamp 17554428 18205391>
18:25:56.219876 IP (tos 0x0, ttl 64, id 10034, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.58961 > 192.168.0.101.111: ., cksum 0xa41f (correct), ack 33 win 46 <nop,nop,timestamp 18205396 17554428>
18:25:56.219911 IP (tos 0x0, ttl 64, id 10035, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.58961 > 192.168.0.101.111: F, cksum 0xa41e (correct), 61:61(0) ack 33 win 46 <nop,nop,timestamp 18205396 17554428>
18:25:56.219957 IP (tos 0x0, ttl 64, id 9858, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.67.0 > 192.168.0.101.2049: 0 proc-285212672
18:25:56.228583 IP (tos 0x0, ttl 64, id 40581, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.101.111 > 192.168.0.67.58961: F, cksum 0xa175 (correct), 33:33(0) ack 62 win 724 <nop,nop,timestamp 17554430 18205396>
18:25:56.228605 IP (tos 0x0, ttl 64, id 10036, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.58961 > 192.168.0.101.111: ., cksum 0xa419 (correct), ack 34 win 46 <nop,nop,timestamp 18205398 17554430>
18:25:56.229112 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.101.2049 > 192.168.0.67.0: reply ok 0 proc-285212672
18:25:56.229130 IP (tos 0x0, ttl 64, id 9859, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.46274 > 192.168.0.101.2049: ., cksum 0x4f86 (correct), ack 1881580284 win 46 <nop,nop,timestamp 18205398 17554430>
18:25:56.229156 IP (tos 0x0, ttl 64, id 9860, offset 0, flags [DF], proto TCP (6), length 96) 192.168.0.67.248749821 > 192.168.0.101.2049: 44 null
18:25:56.237847 IP (tos 0x0, ttl 64, id 32508, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.101.2049 > 192.168.0.67.46274: ., cksum 0x4cb2 (correct), ack 44 win 724 <nop,nop,timestamp 17554432 18205398>
18:25:56.238163 IP (tos 0x0, ttl 64, id 32509, offset 0, flags [DF], proto TCP (6), length 80) 192.168.0.101.2049 > 192.168.0.67.248749821: reply ok 28 null
18:25:56.238178 IP (tos 0x0, ttl 64, id 9861, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.46274 > 192.168.0.101.2049: ., cksum 0x4f39 (correct), ack 29 win 46 <nop,nop,timestamp 18205401 17554432>
18:25:56.238205 IP (tos 0x0, ttl 64, id 9862, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.46274 > 192.168.0.101.2049: F, cksum 0x4f38 (correct), 44:44(0) ack 29 win 46 <nop,nop,timestamp 18205401 17554432>
18:25:56.238258 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 84) 192.168.0.67.32981 > 192.168.0.101.111: UDP, length 56
18:25:56.250661 IP (tos 0x0, ttl 64, id 32510, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.101.2049 > 192.168.0.67.46274: F, cksum 0x4c8e (correct), 29:29(0) ack 45 win 724 <nop,nop,timestamp 17554435 18205401>
18:25:56.250680 IP (tos 0x0, ttl 64, id 9863, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.67.46274 > 192.168.0.101.2049: ., cksum 0x4f31 (correct), ack 30 win 46 <nop,nop,timestamp 18205404 17554435>
18:25:56.261827 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 56) 192.168.0.101.111 > 192.168.0.67.32981: UDP, length 28
18:25:56.261907 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 68) 192.168.0.67.32981 > 192.168.0.101.839: UDP, length 40
18:25:56.268873 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 52) 192.168.0.101.839 > 192.168.0.67.32981: UDP, length 24
18:25:56.269018 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:25:56.677584 IP (tos 0x0, ttl 255, id 0, offset 0, flags [DF], proto UDP (17), length 71) 192.168.0.101.5353 > 224.0.0.251.5353: 0 PTR (QM)? 67.0.168.192.in-addr.arpa. (43)
18:25:59.265674 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:25:59.268134 IP (tos 0xc0, ttl 64, id 8555, offset 0, flags [none], proto ICMP (1), length 140) 192.168.0.101 > 192.168.0.67: ICMP 192.168.0.101 udp port 839 unreachable, length 120
IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:02.265706 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:02.273219 IP (tos 0xc0, ttl 64, id 8556, offset 0, flags [none], proto ICMP (1), length 140) 192.168.0.101 > 192.168.0.67: ICMP 192.168.0.101 udp port 839 unreachable, length 120
IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:05.265648 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:05.306662 IP (tos 0xc0, ttl 64, id 8557, offset 0, flags [none], proto ICMP (1), length 140) 192.168.0.101 > 192.168.0.67: ICMP 192.168.0.101 udp port 839 unreachable, length 120
IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:08.265661 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:08.270394 IP (tos 0xc0, ttl 64, id 8558, offset 0, flags [none], proto ICMP (1), length 140) 192.168.0.101 > 192.168.0.67: ICMP 192.168.0.101 udp port 839 unreachable, length 120
IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:11.265643 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:11.270223 IP (tos 0xc0, ttl 64, id 8559, offset 0, flags [none], proto ICMP (1), length 140) 192.168.0.101 > 192.168.0.67: ICMP 192.168.0.101 udp port 839 unreachable, length 120
IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:14.265659 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 112) 192.168.0.67.818 > 192.168.0.101.839: UDP, length 84
18:26:14.279410 IP (tos 0xc0, ttl 64, id 8560, offset 0, flags [none], proto ICMP (1), length 140) 192.168.0.101 > 192.168.0.67: ICMP 192.168.0.101 udp port 839 unreachable, length 120
 
  


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