Packet loss problem

[Petri Helenius]

You probably need to install a service to the "internet background 
radiation" ports.
Look at the "samba" port, it´ll receive packets on the ports most 
virused microsoft
clients send to random destination addresses.

Pete


Colin Watson wrote:

>Hi, I've got a rather strange issue with UDP loss (at least I think it is) on my network, and frankly - I'm not sure it's me (think it might be the upstream providers stuff). Basically, the situation is this, FreeBSD 4.8 box connects to the upstream provider, and another one at another location acts as a gateway for the customers. The gateway box has very high 'drops' on it's UDP sockets, making streaming stuff awful - and output of netstat -s (UDP,TCP & IP only) on the gateway box is shown at the end of this post. My particular concern is these lines in the UDP output "41738 datagrams received
>  / 33104 broadcast/multicast datagrams dropped due to no socket " which seems an inordinatly high amount. There are no drops due to full socket buffers, although I have recompiled the kernel with nmbclusters=8192 and Maxusers=1024 (to increase number of available sockets - kern.ipc.maxsockets to 9391), still the loss occurs. Any suggestions, and could someone explicitly explain what "broadcast/multicast datagrams dropped due to no socket"  means.
>
>Many Thanks
>
>
>Colin.
>
>---> Output of netstat -s on Gateway Box ----->
>
>tcp:
>        40102 packets sent
>                14837 data packets (1080215 bytes)
>                23 data packets (29468 bytes) retransmitted
>                0 resends initiated by MTU discovery
>                17949 ack-only packets (669 delayed)
>                0 URG only packets
>                0 window probe packets
>                6924 window update packets
>                370 control packets
>        46602 packets received
>                10485 acks (for 1080288 bytes)
>                227 duplicate acks
>                0 acks for unsent data
>                31029 packets (31656794 bytes) received in-sequence
>                132 completely duplicate packets (177030 bytes)
>                0 old duplicate packets
>                9 packets with some dup. data (3920 bytes duped)
>                7375 out-of-order packets (9107920 bytes)
>                0 packets (0 bytes) of data after window
>                0 window probes
>                11 window update packets
>                0 packets received after close
>                0 discarded for bad checksums
>                0 discarded for bad header offset fields
>                0 discarded because packet too short
>        182 connection requests
>        14 connection accepts
>        0 bad connection attempts
>        0 listen queue overflows
>        190 connections established (including accepts)
>        258 connections closed (including 1 drop)
>                19 connections updated cached RTT on close
>                19 connections updated cached RTT variance on close
>                9 connections updated cached ssthresh on close
>        5 embryonic connections dropped
>        9539 segments updated rtt (of 9546 attempts)
>        9 retransmit timeouts
>                0 connections dropped by rexmit timeout
>        0 persist timeouts
>                0 connections dropped by persist timeout
>        0 keepalive timeouts
>                0 keepalive probes sent
>                0 connections dropped by keepalive
>        1 correct ACK header prediction
>        27603 correct data packet header predictions
>        15 syncache entries added
>                1 retransmitted
>                0 dupsyn
>                0 dropped
>                14 completed
>                0 bucket overflow
>                0 cache overflow
>                1 reset
>                0 stale
>                0 aborted
>                0 badack
>                0 unreach
>                0 zone failures
>        0 cookies sent
>        0 cookies received
>udp:
>        41738 datagrams received
>        0 with incomplete header
>        0 with bad data length field
>        0 with bad checksum
>        0 with no checksum
>        8443 dropped due to no socket  
>        33104 broadcast/multicast datagrams dropped due to no socket  <-- My Particular Concern
>        0 dropped due to full socket buffers
>        0 not for hashed pcb
>        191 delivered
>        254 datagrams output
>ip:
>        28432403 total packets received
>        9 bad header checksums
>        0 with size smaller than minimum
>        211 with data size < data length
>        0 with ip length > max ip packet size
>        0 with header length < data size
>        0 with data length < header length
>        0 with bad options
>        0 with incorrect version number
>        2585861 fragments received
>        0 fragments dropped (dup or out of space)
>        57 fragments dropped after timeout
>        1292902 packets reassembled ok
>        9414002 packets for this host
>        2 packets for unknown/unsupported protocol
>        17696404 packets forwarded (0 packets fast forwarded)
>        16337 packets not forwardable
>        0 packets received for unknown multicast group
>        0 redirects sent
>        15047419 packets sent from this host
>        0 packets sent with fabricated ip header
>        0 output packets dropped due to no bufs, etc.
>        26 output packets discarded due to no route
>        97835 output datagrams fragmented
>        195670 fragments created
>        0 datagrams that can't be fragmented
>        0 tunneling packets that can't find gif
>        0 datagrams with bad address in header
>
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