Question : Massive UDP Broadcast, destination port 1100

Hello All,

Quick overview of our network. We have a class c block of ips (192.168.0.0 255.255.252.0) that connects our end users and servers. A couple of months ago there was some problems with our mail flow from web server to exchange. A consultant came in a setup a separate network on top of current (10.100.100.0 255.255.255.0) He setup no routes, nothing he only bound an extra IP address to all of our mail related servers.

The problem we are having now is our UDP traffic is exceeding our TCP traffic. It looks the source is from 10.100.100.10 which our main web server, running Win2k SP4 & IIS5. The broadcast is starting to cripple our network as each device is responding to the UDP broadcast. Here is a sample sniff of our network. Any ideas, suggestions, questions are welcome.  Thnx.


"33", "2.592408", "10.100.100.10", "10.100.100.255", "UDP", "Source port: 2722  Destination port: 1100"
"34", "2.597436", "192.168.0.217", "192.168.3.255", "UDP", "Source port: 2723  Destination port: 1100"
"35", "2.597814", "192.168.1.21", "192.168.3.255", "UDP", "Source port: 2724  Destination port: 1100"
"36", "2.598122", "192.168.2.2", "192.168.3.255", "UDP", "Source port: 2725  Destination port: 1100"
"37", "2.598726", "192.168.2.3", "192.168.3.255", "UDP", "Source port: 2726  Destination port: 1100"
"38", "2.599759", "192.168.2.6", "192.168.3.255", "MGCP", ""
"39", "2.600229", "192.168.2.7", "192.168.3.255", "UDP", "Source port: 2729  Destination port: 1100"
"40", "2.601448", "192.168.2.8", "192.168.3.255", "UDP", "Source port: 2730  Destination port: 1100"
"41", "2.602376", "192.168.2.9", "192.168.3.255", "UDP", "Source port: 2731  Destination port: 1100"
"42", "2.602815", "192.168.2.10", "192.168.3.255", "UDP", "Source port: 2732  Destination port: 1100"

Answer : Massive UDP Broadcast, destination port 1100

Do you use a remote backup service?  Perhaps something called Double-Take http://www.nsisoftware.com/what-we-offer/double-take/

This is a port they use
http://www.lyonware.co.uk/PDFs/DT-WHITE/DT%20Firewall.pdf

Found at
http://www.bekkoame.ne.jp/~s_ita/port/port1-99.html

1100 tcp/udp mctp MCTP
1100 tcp/udp # Double-Take
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