[Discuss] Network IP Conflicts and Dropped Samba Connections Oh My!
Eric Chadbourne
So I have these two problems.
1. On the company shared drive (samba) once in a while people report
microshaft word files getting locked and then they can't use them until
they delete the lock files, but it's only one person using the file.
The samba server has been running almost a year with zero problems until
this recent complaint from a couple of users.
2. Staff is occasionally getting IP conficts. I've checked to make
sure my servers have the proper static IPs and that the Comcast SMC
Networks router doesn't use these addresses in it's dns range. We have
a couple of wireless routers and I'm verifying now they are not the cause.
Here's my current guess as to what's happening.
1. One of the cicso switches burned out a fan which I replaced. I
think the old bugger is reaching it's end of life. Maybe this is
intermittently screwing up samba connections?
2. The IP conflicts are because the smc router has the hiccups and we
need to purchase a real business router / vpn.
I'm also googling for a good network monitor application that can run on
Ubuntu and could maybe help me figure out which (if any) switch is in
poor health.
All clues welcome.
Thanks!
- Eric C
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Bill Bogstad
> Hi All,
>
> So I have these two problems.
>
> 2. Staff is occasionally getting IP conficts. I've checked to make sure my
> servers have the proper static IPs and that the Comcast SMC Networks router
> doesn't use these addresses in it's dns range. We have a couple of wireless
> routers and I'm verifying now they are not the cause.
>
> Here's my current guess as to what's happening.
> 2. The IP conflicts are because the smc router has the hiccups and we need
> to purchase a real business router / vpn.
Are the conflicting IP addresses in the DHCP range that the SMC is
managing? That's not clear to me from your description of the
problem. If they are, I might guess that the SMC is periodically
resetting itself and forgetting about addresses it has already
allocated. If you have the ability to setup a monitor port somewhere
in your network infrastructure, you might try setting up a sniffer
there to capture just DHCP packets. If not, you still might try
this. You'll only see the initial broadcast packets of DHCP address
allocation, but it still might give you some useful clues. If the SMC
has an "uptime" status page, that might tell you something as well.
Good Luck,
Bill Bogstad
Guy Gold
> 1. One of the cicso switches burned out a fan which I replaced. I
> think the old bugger is reaching it's end of life. Maybe this is
> intermittently screwing up samba connections?
Never say never in the happy world of Telecom, but the switch would
not be my first target. Its been a while since my last Samba T-shoot
(luckily), I'll leave this one to others.
> 2. Staff is occasionally getting IP conficts. I've checked to make
> sure my servers have the proper static IPs and that the Comcast SMC
> Networks router doesn't use these addresses in it's dns range. We
> have a couple of wireless routers and I'm verifying now they are not
> the cause.
>
1.Can you post the exact message that implies of the IP conflict ?
2.Do you have more then one DHCP server on the LAN ?
> I'm also googling for a good network monitor application that can
> run on Ubuntu and could maybe help me figure out which (if any)
> switch is in poor health.
TCPdump, it's cross-distro, it takes longer to master then GUI
sniffers, like Wireshark, but, like most shell-based tools, it's worth
the invsetment.
--
**Thank you for sending plain text messages to this address**
Guy Gold
Jerry Feldman
> Hi All,
>
> So I have these two problems.
>
> 1. On the company shared drive (samba) once in a while people report
> microshaft word files getting locked and then they can't use them
> until they delete the lock files, but it's only one person using the
> file. The samba server has been running almost a year with zero
> problems until this recent complaint from a couple of users.
>
> 2. Staff is occasionally getting IP conficts. I've checked to make
> sure my servers have the proper static IPs and that the Comcast SMC
> Networks router doesn't use these addresses in it's dns range. We
> have a couple of wireless routers and I'm verifying now they are not
> the cause.
>
> Here's my current guess as to what's happening.
>
> 1. One of the cicso switches burned out a fan which I replaced. I
> think the old bugger is reaching it's end of life. Maybe this is
> intermittently screwing up samba connections?
>
> 2. The IP conflicts are because the smc router has the hiccups and we
> need to purchase a real business router / vpn.
>
> I'm also googling for a good network monitor application that can run
> on Ubuntu and could maybe help me figure out which (if any) switch is
> in poor health.
(eg connection) goes away. I've seen it here where I have left word or
PPT up on my work PC overnight, and the connection to the office servers
was dropped overnight.
Most routers, even the cheap ones, tend to reissue the same IP address
to the same MAC, but I have seen a different IP issued. In terms of
wireless, I have 2 wireless routers in my office, but neither of them
are DHCP servers, and I rely on our office SonicWall for that. Also
noting both my smartphone and netbook behavior, sometimes they will
connect to the other wireless in the office in preference to the one on
my desk.
--
Jerry Feldman <g...@blu.org>
Boston Linux and Unix
PGP key id:3BC1EB90
PGP Key fingerprint: 49E2 C52A FC5A A31F 8D66 C0AF 7CEA 30FC 3BC1 EB90
Eric Chadbourne
> Are the conflicting IP addresses in the DHCP range that the SMC is
> managing? That's not clear to me from your description of the
> problem. If they are, I might guess that the SMC is periodically
> resetting itself and forgetting about addresses it has already
> allocated. If you have the ability to setup a monitor port somewhere
> in your network infrastructure, you might try setting up a sniffer
> there to capture just DHCP packets
Yep the SMC is managing all DHCP.
On 03/19/2012 11:26 AM, Guy Gold wrote:
> 1.Can you post the exact message that implies of the IP conflict ?
> 2.Do you have more then one DHCP server on the LAN ?
Only one DHCP server. It's just windows boxes giving a generic pop up
complaint about an IP conflict. Reboot seems to resolve the issue.
> TCPdump, it's cross-distro, it takes longer to master then GUI
> sniffers, like Wireshark, but, like most shell-based tools, it's worth
> the invsetment.
Cool I'll check it out. Sounds like a fun tool to learn more about my
little LAN.
Well after digging around some today I found that I did have a not too
often used server with the same static IP as my samba server. Doh! So
I'm _hoping_ that will fix the locked files issue. I had no complaints
today about it. :)
For the IP conflicts I changed the setting to update addresses on the
SMC device to two days. It was 2 weeks. This is just me guessing though.
I'll do some more digging around. Many thanks for the excellent feed back!
- Eric C
The one who wears too many hats.
Tom Metro
>> TCPdump, it's cross-distro, it takes longer to master then GUI
>> sniffers, like Wireshark, but, like most shell-based tools, it's worth
>> the invsetment.
>
> Cool I'll check it out. Sounds like a fun tool to learn more about my
> little LAN.
One of the great things about running a third party firmware on your
broadband router is that you can run tcpdump on it. (Available as an
optware package.) Something you'll likely need rarely on a home network,
but really handy when you do.
-Tom
--
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/