Re: Kerberos UDP vs TCP

Various network devices and improperly configured network cards are what I most often see screwing up the UDP packet delivery. I have had to use TCP to troubleshoot but it was always to help identify that some network component was screwing up.

UDP is used initially because that is the standard. It generally works just fine, in the hundreds of networks I have experienced first hand and thousands I have dealt with second/third hand the number of times I have seen UDP issues is less than 15.

TCP does add a good amount of overhead and I would recommend doing a network impact study before considering switching whole hog to TCP. Actually I would say go find why UDP isn't working, it will take some time with a sniffer to find out what device is throwing out the packets. but once you determine that you can investigate it and correct it. This can usually, in my experience, be fixed by correcting configurations or updating firmwares of various network devices.


--
Joe Richards Microsoft MVP Windows Server Directory Services
Author of O'Reilly Active Directory Third Edition
www.joeware.net


---O'Reilly Active Directory Third Edition now available---

http://www.joeware.net/win/ad3e.htm


paolo valsecchi wrote:
Hi everybody
I'm facing some problems with Kerberos authentication using UDP protocol. As suggested by Microsoft using TCP protocol the problem has been solved instead.

Questions:
Why Microsoft uses UDP by default if there are authentication problems?
What would be the global impact on the network (WAN) using Kerberos authentication through TCP? Would it be a suitable solution?

Any help really appreciated.

.

Relevant Pages

  • Re: Stand Alone DHCP Servers and Windows 2000
    ... On our network the clients are allowed to talk to the domain controller ... Kerberos-Sec (UDP) ... Microsoft CIFS (TCP) ... which segments and which computers use specific protocols. ...
    (microsoft.public.windows.server.networking)
  • Re: Kerberos UDP vs TCP
    ... The main reason for using UDP by default is that it's lightweight compared ... UDP starts having problem if the network is not reliable, i.e. busy network, ... slow links, or has packet loss. ... The advantage of using TCP is that it uses ...
    (microsoft.public.security)
  • Re: Log Out Issues
    ... > I would be quite happy to use TCP to save headaches, ... > ive read during my learning, UDP is the way to go for internet games. ... UDP is faster, in this context, mostly because it doesn't care so much about ... If the network has a little hiccup, and you're using UDP, all that happens ...
    (microsoft.public.win32.programmer.networks)
  • Re: logging in but then loss of domain connection
    ... > It sounds like the workstation is unable to find the Domain controller. ... > happens if you connect the laptop to the network using a network cable? ... We have seem issues whereby the UDP ... > Kerberos to use TCP by making a registry change. ...
    (microsoft.public.windows.server.sbs)
  • NFS problem with recent 2.6 kernels (also serial console weirdness)
    ... 100000 2 tcp 111 portmapper ... 100000 2 udp 111 portmapper ... mounted filesystem with ordered data mode. ... Mounted root (ext3 filesystem) readonly. ...
    (Linux-Kernel)