Wireshark-users: Re: [Wireshark-users] Please help decode DCERPC packets between W2K,	a DC, and a
      
      
Hmmm...since this was probably a result of a Global Address 
List query, what might the appropriate choice in the Decode As 
Window?
 
- Phil
dcerpc is a transport for interfaces/protocols transported atop 
it.
due to the way dcerpc works   the information about 
exactly which protocol is transported atop it is only present inside the initial 
dcerpc BIND calls    that is sued to attach a specific 
application protocol to a dcerpc session. 
unless wireshark has 
actually seen the initial bind call that occurs at the very beginning of the 
session    it is not possible to know what protocol is 
transported atop dcerpc and thus it can not be decoded.
If you 
KNOW it is exchange   you can manually force wireshark to decode this 
payload as a specific such protocol using DECODE AS.
If it is 
exchange    it is likely that the protocol transported is either 
MAPI or NSPI 
note that since these two protocols are undocumented 
and very little interest for them exist in the wireshark 
community    wireshark will still not be able to do much more 
than tell you the name of that particular procedure   but nothing 
more. 
wireshark knows however only the procedure name for 
procedures 0-9 for MAPI and not procedure 11.
procedure 11 for NAPI is 
called   NspiModProps    but wireshark can not decode 
the payload for it.
On 8/18/06, Schlesinger, 
Philip <pschlesinger@xxxxxxxxxxx> 
wrote:
  
  
  Hi all.  We're trying to figure out why 
  Outlook periodically freezes on the machines in our department (my company 
  uses Exchange Server - either 2000 or 2003).  So I set up Wireshark to 
  record data to two one-megabyte files in a ring - it has been running for days 
  now.  
  Today, I had a freeze-up, so I opened up a second 
  Wireshark and peeked inside the newest log file.  My Outlook and Exchange 
  appear to be just peachy keen one moment:
  #3108 
89.038216 
Source <my 
  IP> 
Destination <exchange svr 
  IP> 
DCERPC Request: call_id:417 opnum: 
  11 ctx_id: 0 
  #3109 
89.039143 
Source <exchange svr 
  IP> 
Destination <my IP> 
  
DCERPC Response: call_id:417 opnum: 11 
  And shortly thereafter: 
  #3145 
90.803519 
Source <my 
  IP> 
Destination <the company's domain 
  controller> 
DCERPC Request: call_id: 3 
  opnum: 12 ctx_id: 0 
(note: I log into the 
  company domain, but my computer is a member of a department domain, and that 
  department domain trusts my company's domain)
  #3171, #3238, #3371, #3447, and #3576 are all TCP 
  Retransmissions of #3145 
  Finally, a TCP SYN command occurs (I've seen it in 
  the past, but I set up too small of a log file size) occurs and everything 
  seems to kick back into gear.  
  Any ideas? 
  What's also weird is that on the call to the 
  company domain controller includes a line in the DCE RPC Request description: 
  "[No bind info for this interface Context ID - capture start too late?]"  
  
  What does this mean? 
  
  
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