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Re: [Xen-users] Massive numbers of dropped packets / ssh problems
That was my gut instinct, as well, Tom, but if I let the connection
sit, it will eventually time out after a few minutes.
And it still doesn't explain the barrage of dropped packets on peth1.
I have to admit that this situation is beyond my understanding and
skills which is why I came to the lit for help.
Could it simply be that whatever it is that is dealing with the now 89
billion dropped packets is simply overloaded and can't provide a
timely response to a normal SSH request? I mean 89 billion in a week
is 140,000 in a second. What the heck could be going on to provide
that many dropped packets? I just don't get it.
I'm now leaning towards some sort of driver problem with the NIC card
since, upon reboot it shows 2 billion packets dropped. How can this
be? It must be a problem with the network card.
As for SSH problems could it be an ARP problem? I know that my
upstream router does some sort of ARP caching. I have not yet
established any patterns here, but there are a few tests I want to run.
Thanks,
--Joel
On Mar 7, 2009, at 9:39 AM, tom.ashley@xxxxxxxxx wrote:
That actaully sounds like a reverse dns lookup issue from your server.
Make sure the ssh server can resolve the ip you are coming from.
Tom
Sent using BlackBerry® from Orange
-----Original Message-----
From: Joel Richard <xen@xxxxxxxxxxxxxxx>
Date: Sat, 7 Mar 2009 08:08:49
To: <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-users] Massive numbers of dropped packets / ssh problems
Good morning,
I'm hoping that someone can help me out with this. I recently moved a
running server from an internal network to a public-facing network
(moved from our office to a data center)
Prior to this, we had no trouble with the server, but since we've put
it on the net and gave it some public IPs (versus the 192.168.x.x
addresses it had before) we've had trouble with SSH and Web
connections onto one of the DomU servers (possibly all of them). That
is, sometimes when we connect from SSH or HTTP, it will sometimes
"time out" somehow (not your usual connection timed out) and we need
to try again a couple of times to get the server to respond. It seems
to happen most when the server has been idle for some time, like first
thing in the morning.
On the Dom0 if I do an ifconfig, I get the info that's at the bottom
of this message (IPs have been changed to protect the innocent) The
server has 4 DomU's running on it.
Note that the peth1 interface has 79 billion dropped packets. The
server has been running for a week. My first thought is "what the
hell?" :) I can't find those dropped packets with tcpdump and yet I am
convinced that this is a problem.
When we SSH into the server (the DomU), sometimes it will hang with
this information:
(my laptop) $ ssh -v XXX.XXX.XXX.XXX
OpenSSH_5.0p1, OpenSSL 0.9.7l 28 Sep 2006
debug1: Reading configuration data /Users/joel/.ssh/config
debug1: Applying options for dev
debug1: Reading configuration data /etc/ssh_config
debug1: Connecting to dev.richard-group.com [XXX.XXX.XXX.XXX] port 22.
debug1: Connection established.
debug1: identity file /Users/joel/.ssh/identity type -1
debug1: identity file /Users/joel/.ssh/id_rsa type 1
debug1: identity file /Users/joel/.ssh/id_dsa type 2
Yes, that's where it stops. It's already established the connection,
but it doesn't continue. It initially sounds like an SSH problem, but
it seems more to me something possibly between the Dom0 and the DomU.
I do not have this problem with ssh on a real server on the same
network that is not using Xen.
To clarify, I am using Debian Etch, Xen 3.0.3, AMD Phenom CPUs,
2.6.18-6-xen-amd64 #1 SMP kernel. We're using the onboard NIC.
Can anyone help?
Thanks a lot.
--Joel
(dom0) # ifconfig
eth1 Link encap:Ethernet HWaddr 00:1F:D0:99:C8:1D
inet addr:XXX.XXX.XXX.XXX Bcast:XXX.XXX.XXX.XXX Mask:
255.255.255.192
inet6 addr: XXX.XXX.XXX.XXX/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:790038 errors:0 dropped:0 overruns:0 frame:0
TX packets:30111 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:259565273 (247.5 MiB) TX bytes:8294720 (7.9 MiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
peth1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:3231189 errors:0 dropped:79653025568 overruns:0
frame:0
TX packets:1839869 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1834207650 (1.7 GiB) TX bytes:617376732 (588.7 MiB)
Interrupt:16 Base address:0xa000
vif0.1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:30111 errors:0 dropped:0 overruns:0 frame:0
TX packets:790038 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8294720 (7.9 MiB) TX bytes:259565273 (247.5 MiB)
vif1.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:1621897 errors:0 dropped:0 overruns:0 frame:0
TX packets:2841674 errors:0 dropped:1371 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:437418179 (417.1 MiB) TX bytes:2168128688 (2.0 GiB)
vif2.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:10114591 errors:0 dropped:0 overruns:0 frame:0
TX packets:11032176 errors:0 dropped:244457 overruns:0
carrier:0
collisions:0 txqueuelen:0
RX bytes:8708636564 (8.1 GiB) TX bytes:10165626759 (9.4 GiB)
vif4.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:10714696 errors:0 dropped:0 overruns:0 frame:0
TX packets:10554522 errors:0 dropped:220230 overruns:0
carrier:0
collisions:0 txqueuelen:0
RX bytes:10211262961 (9.5 GiB) TX bytes:8503978649 (7.9 GiB)
vif8.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:6432 errors:0 dropped:0 overruns:0 frame:0
TX packets:39471 errors:0 dropped:50 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1485151 (1.4 MiB) TX bytes:12072170 (11.5 MiB)
xenbr1 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:579865 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:113821662 (108.5 MiB) TX bytes:0 (0.0 b)
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