#23 Daemon mode does not allow return traffic when using UDP

[Jason Frisvold]

Using both iPerf 2.0.2 and 2.0.4 for testing. Server side is configured as such :

./iperf -s -u -D

Client side is run as follows :

./iperf -c 10.34.93.243 -u -r

Using either the -r or -d flags, only the initial traffic *to* the server seems to work. Output from one client session is as follows :

./iperf -c 10.34.93.243 -u -r
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size: 107 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 10.34.93.243, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size: 107 KByte (default)
------------------------------------------------------------
[ 4] local 10.34.93.105 port 33473 connected with 10.34.93.243 port 5001
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.1 sec 1.24 MBytes 1.03 Mbits/sec
[ 4] Sent 883 datagrams
[ 4] WARNING: did not receive ack of last datagram after 10 tries.

Of note here is the WARNING at the end. If the server is run in the foreground, that warning does not appear.

Also note, while RFC-1918 IPs are used, there is no NAT device or firewall present. The client and server are connected to the same Ethernet switch, allowing a full 100 Mbps full-duplex connection.

[Bjoern Hagemeier]

This seems to be still valid for 2.0.5. Does anyone work on it?

[Dave Kruger]

I am also seeing this in 2.0.5. @bjoernh did you ever manage to find a workaround?