RX-DRP packets ??

Hello,

when I do a netstat -ni, i see dropped packets on my external intf.
avout 80 pkts/sec. Is there a way to see what is dropped, and why ?

There is no collisions on the link.

I run a linux 2.6.16.20
rgds.

On 09/07/2007 04:47 PM, Miss Terre wrote:
> Hello,
>
> when I do a netstat -ni, i see dropped packets on my external intf.
> avout 80 pkts/sec. Is there a way to see what is dropped, and why ?
>
> There is no collisions on the link.
>
> I run a linux 2.6.16.20
> rgds.

Usenet is not a chat room, please compose your questions deliberately,
provide enough of the information and do give them a reading before you
post. FYI, almost all this is being archived by Google and, or many a
other such services.

Hum, Is there a way for us to guess, what kind of link are you talking
about, wired or wireless?

Kindly note that the -n in this case of netstat is ambiguous.

Are you using netfilter/iptables firewall? If yes, is that configured
properly? Have you checked your firewall logs?

--
Dr Balwinder S "bsd" Dheeman Registered Linux User: #229709
Anu'z Linux@HOME Machines: #168573, 170593, 259192
Chandigarh, UT, 160062, India Gentoo, Fedora, Debian/FreeBSD/XP
Home: http://cto.homelinux.net/~bsd/ Visit: http://counter.li.org/

In article <(E-Mail Removed)>,
(E-Mail Removed) says...
> On 09/07/2007 04:47 PM, Miss Terre wrote:
> > Hello,
> >
> > when I do a netstat -ni, i see dropped packets on my external intf.
> > avout 80 pkts/sec. Is there a way to see what is dropped, and why ?
> >
> > There is no collisions on the link.
> >
> > I run a linux 2.6.16.20
> > rgds.
>
> Usenet is not a chat room, please compose your questions deliberately,
> provide enough of the information and do give them a reading before you
> post. FYI, almost all this is being archived by Google and, or many a
> other such services.
>
> Hum, Is there a way for us to guess, what kind of link are you talking
> about, wired or wireless?
>
> Kindly note that the -n in this case of netstat is ambiguous.
>
> Are you using netfilter/iptables firewall? If yes, is that configured
> properly? Have you checked your firewall logs?
>
>

Ok, here is the informations.
When I look at my network interfaces, by doing a "netstat -i" (ok, you
can skip the n) I see that there are some packets dropped.
I have a network card in ISA slot, which is a HP PCLAN plus, with a
wired connection to a routeur.

What I've seen in google is that dropped packets are due (maybe) to a
lack of memory. As the machine is an old 486 with 20Mb ram, it could be.

But, I'd like to investigate on the system why these packets are
dropped.

I also use iptables (for many years now) and I know there is no relation
with this, just because without iptables, the same issue occurs.

Does anyone know how to investigate about this ? the packets are dropped
by the kernel (not the netfilter part) but, why ?

Many thanks.

2007-09-7, 15:53(+02), Miss Terre:
[...]
> When I look at my network interfaces, by doing a "netstat -i" (ok, you
> can skip the n) I see that there are some packets dropped.
> I have a network card in ISA slot, which is a HP PCLAN plus, with a
> wired connection to a routeur.
>
> What I've seen in google is that dropped packets are due (maybe) to a
> lack of memory. As the machine is an old 486 with 20Mb ram, it could be.
>
> But, I'd like to investigate on the system why these packets are
> dropped.
[...]

netstat reads /proc/net/dev (confirmed if you do a strace
netstat -i).

net/core/dev.c shows that the RX-DRP column is the sum of the
rx_dropped + rx_missed_errors fields of the device stat
structure.

Look for rx_dropped and rx_missed_errors in drivers/net/hp100.c.
You'll see that it's only for memory allocation issues. So
google didn't lie to you.

--
Stéphane

On 09/07/2007 07:23 PM, Miss Terre wrote:
> In article <(E-Mail Removed)>,
> (E-Mail Removed) says...
>> On 09/07/2007 04:47 PM, Miss Terre wrote:
>>> Hello,
>>>
>>> when I do a netstat -ni, i see dropped packets on my external intf.
>>> avout 80 pkts/sec. Is there a way to see what is dropped, and why ?
>>>
>>> There is no collisions on the link.
>>>
>>> I run a linux 2.6.16.20
>>> rgds.
>> Usenet is not a chat room, please compose your questions deliberately,
>> provide enough of the information and do give them a reading before you
>> post. FYI, almost all this is being archived by Google and, or many a
>> other such services.
>>
>> Hum, Is there a way for us to guess, what kind of link are you talking
>> about, wired or wireless?
>>
>> Kindly note that the -n in this case of netstat is ambiguous.
>>
>> Are you using netfilter/iptables firewall? If yes, is that configured
>> properly? Have you checked your firewall logs?
>>
>>
>
> Ok, here is the informations.
> When I look at my network interfaces, by doing a "netstat -i" (ok, you
> can skip the n) I see that there are some packets dropped.
> I have a network card in ISA slot, which is a HP PCLAN plus, with a
> wired connection to a routeur.

ok.

> What I've seen in google is that dropped packets are due (maybe) to a
> lack of memory. As the machine is an old 486 with 20Mb ram, it could be.

I for one would prefer installing a tiny and, or older distro on such a
machine, say DSL (the Damn Small Linux).

> But, I'd like to investigate on the system why these packets are
> dropped.

NP, most of the NIC as well as other driver modules can allow you to
turn on debugging as an option; though this may quickly fill up you
/var/log disk partition and, or directory. Please check with modinfo how
to turn debugging on for the concerned module.

> I also use iptables (for many years now) and I know there is no relation
> with this, just because without iptables, the same issue occurs.

Have you checked all other relevant log files?

> Does anyone know how to investigate about this ? the packets are dropped
> by the kernel (not the netfilter part) but, why ?

Can't say why your kernel and, or tcp stack is dropping packets, that's
why me too am awaiting for other people over here to come up with some
constructive and, or workable solution.

> Many thanks.

You're welcome!

Hope that helps,
--
Dr Balwinder S "bsd" Dheeman Registered Linux User: #229709
Anu'z Linux@HOME Machines: #168573, 170593, 259192
Chandigarh, UT, 160062, India Gentoo, Fedora, Debian/FreeBSD/XP
Home: http://cto.homelinux.net/~bsd/ Visit: http://counter.li.org/

On 09/07/2007 07:23 PM, Miss Terre wrote:
> In article <(E-Mail Removed)>,
> (E-Mail Removed) says...
>> On 09/07/2007 04:47 PM, Miss Terre wrote:
>>> Hello,
>>>
>>> when I do a netstat -ni, i see dropped packets on my external intf.
>>> avout 80 pkts/sec. Is there a way to see what is dropped, and why ?
>>>
>>> There is no collisions on the link.
>>>
>>> I run a linux 2.6.16.20
>>> rgds.
>> Usenet is not a chat room, please compose your questions deliberately,
>> provide enough of the information and do give them a reading before you
>> post. FYI, almost all this is being archived by Google and, or many a
>> other such services.
>>
>> Hum, Is there a way for us to guess, what kind of link are you talking
>> about, wired or wireless?
>>
>> Kindly note that the -n in this case of netstat is ambiguous.
>>
>> Are you using netfilter/iptables firewall? If yes, is that configured
>> properly? Have you checked your firewall logs?
>>
>>
>
> Ok, here is the informations.
> When I look at my network interfaces, by doing a "netstat -i" (ok, you
> can skip the n) I see that there are some packets dropped.
> I have a network card in ISA slot, which is a HP PCLAN plus, with a
> wired connection to a routeur.
>
> What I've seen in google is that dropped packets are due (maybe) to a
> lack of memory. As the machine is an old 486 with 20Mb ram, it could be.
>
> But, I'd like to investigate on the system why these packets are
> dropped.
>
> I also use iptables (for many years now) and I know there is no relation
> with this, just because without iptables, the same issue occurs.
>
> Does anyone know how to investigate about this ? the packets are dropped
> by the kernel (not the netfilter part) but, why ?
>
> Many thanks.

You're welcome!

Oh, on a 486/20Mb machine, IMHO you need to give DSL (Damn Small Linux)
or other such distro which uses uCLibc instead of glibc, a try.

I think, log files /var/log/kern.log, /var/log/messages and, or
/var/log/syslog can best tell you why the kernel is dropping packets.

OTOH, sysctl(8) and sysctl.conf(5) can be handy for tweaking and, or
tuning around your current kernel's ipv4 parameters.

--
Dr Balwinder S "bsd" Dheeman Registered Linux User: #229709
Anu'z Linux@HOME Machines: #168573, 170593, 259192
Chandigarh, UT, 160062, India Gentoo, Fedora, Debian/FreeBSD/XP
Home: http://cto.homelinux.net/~bsd/ Visit: http://counter.li.org/

In article <(E-Mail Removed)>,
(E-Mail Removed) says...
> You're welcome!
> Oh, on a 486/20Mb machine, IMHO you need to give DSL (Damn Small Linux)
> or other such distro which uses uCLibc instead of glibc, a try.

I didn't know this distribution. I use a Slackware, with a minimum of
customisation I've discovered this distribution in 1993, and I like
it
But, I notice that there is a µClibc that is usable instead of glibc !
great thing to know ! I'll look after that !

> I think, log files /var/log/kern.log, /var/log/messages and, or
> /var/log/syslog can best tell you why the kernel is dropping packets.

messages and syslog are not very helpful for me. You bet I've looked in
But, there is no much than classical informations in it.
Sometime, I see the kernel kills some process to avoid running out of
memory, and maybe during this, packets are dropped.
I'll investigate and tell you

> OTOH, sysctl(8) and sysctl.conf(5) can be handy for tweaking and, or
> tuning around your current kernel's ipv4 parameters.

Thanks, I was playing directly with /proc/sys/net/...... but with
sysctl, it is more elegant

Thanks for your help.