Red Hat Bugzilla – Bug 133032
abnormal network events need to be counted (e.g., dropped UDP packets)
Last modified: 2007-11-30 17:07:04 EST
Customer is migrating from SunOS to Linux and is concerned about the
lack of network related event counters important to their environment.
Customer is primarily concerned with lack of counters for TCP SYN
packets being dropped due to the listen queue being full and UDP
packets being dropped due to the receive queue being full.
I found that a full listen queue is counted and exported via
/proc/net/netstat but netstat(1) does not report that metric.
Customer would like to see this metric reported by netstat(1).
Note that in general any abnormal event should be counted and that
information made available via standard tools (e.g., netstat(1)) as
well as SNMP. On DYNIX/ptx for example the following UDP related
metrics are available, many of which have no Linux analogue:
UDP Statistics (/dev/udp):
137299446 datagrams received
0 datagrams caused pcb cache miss
0 datagrams dropped: packet shorter than header
0 datagrams dropped: checksum error
0 datagrams dropped: data len longer than packet
44091 datagrams dropped: no local port
80 broadcast datagrams dropped: due to no local port
0 datagrams not delivered: input queue full
137068521 datagrams sent
Try netstat -s, it prints out things like:
1 times the listen queue of a socket overflowed
1 SYNs to LISTEN sockets ignored
We report and provide every statistics required by the RFC
MIBs. Therefore I'm closing this.
After looking at the source for netstat I understand why we're not
seeing this data. On my system and the system the customer looked at
the values are zero.
For the record: I consider the current behavior to be broken. The
variables with custom formatting strings are only displayed if the
value is greater than zero. In contrast to the variables without
custom formatting strings which are displayed even if the value is
zero. The current behavior is inconsistent.
Regarding the second part of my defect report. Just because something
isn't required by a RFC doesn't mean it isn't useful. But given your
response I can see there is no point in my filing a separate defect
report just for that issue.
Hello, Kurtis. It sounds like you'd prefer that netstat displays
statistics for all fields whether or not they're non-zero. Assuming
that's the crux of this bug report, let me reopen it and assign it
to the net-tools package maintainer.
(If DaveM thinks I'm doing the wrong thing, he can reclose this bug.)
The problem of netstat -s is that the part from /proc/net/netstat is
not yet documented and that's why the format strings are missing. I
agree that displaing both files are not very good-looking.
Possibilities are either to wait for IBM from whom I've got promise to
document all these items or the drop the second part and keep just
items in which I'm 100% sure about their meaning or to add a new
option for --even_more_verbose netstat -s which will show all items in
New statistics included in net-tools-1.60-52