[TIGGE #CUA-629523]: Re: dataportal not receiving data from tigge-ldm.ecmwf.int

Manuel,

> I attach the report logged by our Sys Admin. I am afraid I cannot add
> anything more to it.
> 
> Cheers,
> Manuel

> I investigated with Manuel.
> 
> It was not possiuble to ldmping tigge-ldm from tigge-ldm
> which implies that the network was not the problem.
> 
> "netstat -an" showed lots of outstanding connections in
> a SYN_RECV state from dataportal (NCAR) and tigge-ldm and
> tigge-portal.
> 
> Active Internet connections (servers and established)
> Proto Recv-Q Send-Q Local Address        Foreign Address       State
> tcp   0      0      0.0.0.0:388          0.0.0.0:*             LISTEN
> tcp   0      0      193.61.196.74:388    128.117.12.2:64900    SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64970    SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64976    SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64908    SYN_RECV
> tcp   0      0      193.61.196.74:388    193.61.196.76:55517   SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64991    SYN_RECV
> tcp   0      0      193.61.196.74:388    193.61.196.76:55531   SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64855    SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64994    SYN_RECV
> tcp   0      0      193.61.196.74:388    193.61.196.76:55520   SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64968    SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:64955    SYN_RECV
> tcp   0      0      193.61.196.74:388    193.61.196.76:55529   SYN_RECV
> tcp   0      0      193.61.196.74:388    128.117.12.2:65003    SYN_RECV
> tcp   0      0      193.61.196.74:388    193.61.196.76:55537   SYN_RECV

The above indicates that the LDM on host tigge-ldm received connection attempts 
from hosts dataportal.ucar.edu and tigge-portal.ecmwf.int.  The connections, 
apparently, remained in the SYN_RECV state.  This is consistent with with the 
TCP layer on host tigge-ldm never receiving the final ACK from the connecting 
hosts.  Because the TCP layer did receive the initial SYN-s from the connecting 
hosts, it is likely that something prevented the transmission of the SYN and 
ACK responses from host tigge-ldm to the connecting hosts.  This same barrier 
might also have prevented the ldmping(1) on host tigge-ldm from connecting to 
the LDM server on that host.

Is it possible that host tigge-ldm was running firewall software and that it 
was preventing incoming TCP connections?

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: CUA-629523
Department: Support IDD TIGGE
Priority: Normal
Status: On Hold