Bug 17181 - UDP random port number not incremented
Summary: UDP random port number not incremented
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: kernel
Version: 6.2
Hardware: i686
OS: Linux
Target Milestone: ---
Assignee: David Miller
QA Contact:
Depends On:
TreeView+ depends on / blocked
Reported: 2000-09-01 15:54 UTC by jkrzyszt
Modified: 2008-05-01 15:37 UTC (History)
0 users

Clone Of:
Last Closed: 2000-09-01 20:35:36 UTC

Attachments (Terms of Use)

Description jkrzyszt 2000-09-01 15:54:45 UTC
All processes opening UDP sockets in order to send data without prior
binding to a speciffic address get the same port number. It goes on until
an error occures during packet reception. After that, an ICMP message "port
xxx unreachable" is send, the random port number is incremeted by 1, and
the situation starts from the beginning.
I am not sure if it is a bug, or an implementation or design feature.
However, servers that receive these ICMP packets treat them as
communication errors an fill error logs with "connection refused" messages.

Comment 1 jkrzyszt 2000-09-01 16:02:35 UTC
BTW, kernel version numbers I have tesed are 2.2.16-3 and 2.2.16-4.lfs

Comment 2 jkrzyszt 2000-09-06 09:18:52 UTC
O.K, so maybe there is a bug in an application.

The application that suffers is "kprop" found in "krb5-server-1.1.1-21"
componnet. It opens a random UDP port and sends a packet to a "kpropd" daemon
listening on the well-known "krb5_prop" port on another machine. It usualy
happens that the answer received from that machine is rejected, and ICMP mesage
"port xxx unreachable" is sent. After that, "kprop" tries again, this time
selecting a random port that's number is higher by 1 than before, and it
However, netowork badwidth is unnecessarily consumed, as well as disk space on
the machine where kpropd error messages are logged.
Could you please reopen this bug, changing the component name to "krb5-server"?


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