Someone on the james user list reported this problem, and I wasn't sure
if it's been patched... they're running against the james 2.0a2 release,
which means they're using mid-Nov 2001 snapshots from Avalon if that
helps. Otherwise just thought I should share this user's notes.
--
Serge Knystautas
Loki Technologies - Unstoppable Websites
http://www.lokitech.com/
--- Begin Message ---
Just a follow-up - I've determined that it takes approximately 1500-1700
tcp connections, one every 5 seconds, to cause this OutOfMemoryError.
Without these connections, my James installation is stable for days. It
still looks like an easy way to take out a james server - in my case
this happens in about 2.2 hours, but I expect that the same effect could
be created by sending the connections faster.
I'm going to have to try going back to James 1.2.1 to see if I can get
around this b/c it's useless in my environment with this kind of bug.
-Brad
Brad Wallace wrote:
>
> Hi All - I'm running James in a load balanced environment (required by
> our policies... ;-) One side effect of this is that the load balancers
> establish repeated TCP connections to the SMTP service and then break
> them (TCP RST or FIN I expect). They do this to verify that the service
> is listening and accepting inbound connections. Right now I'm running
> in debug mode, so these connections are being logged - I've included
> samples below.
>
> Here's the problem - after james has been running for some period of
> time less than 1 week, I get the following on stdout:
>
> Logging Error: Unknown error writing event.
> java.lang.OutOfMemoryError
> <<no stack trace available>>
>
> and then james stops responding. So far I've had to restart james each
> time to get this fixed. I'll admit that the frequent TCP connection
> setups and breakdowns are a quirk of this type of environment, but it
> concerns me also b/c this seems like an easy DOS (Denial of Service)
> attack on a james server - simply establish and break TCP connections
> every 5 seconds or so for a while and it will hang until someone
> restarts it - it's not yet clear exactly how long you have to repeat
> these TCP connections for, but it's somewhere in the hours - days range,
> but not weeks. And every 5 seconds probably isn't frequent enough to
> trigger most firewall's DOS filters, so this is pretty likely to get
> through.
>
> I'm running:
>
> James 2.0a2 with just the SMTP listener (no pop3, nntp, remote admin,
> etc)
> java-1.3.1_02
> Solaris 7
>
> Thanks much for any input.
>
> -Brad
>
> Logs Excerpts:
>
> smtpserver.log:
>
> Tue Apr 23 22:02:58 GMT 2002 [INFO ] (smtpserver): Hello Name is:
> <local machine name>
> Tue Apr 23 22:02:58 GMT 2002 [DEBUG ] (smtpserver): Max message size
> is: 0
> Tue Apr 23 22:02:58 GMT 2002 [INFO ] (smtpserver): Connection from
> <load balancer IP> (<load balancer IP>)
> Tue Apr 23 22:02:58 GMT 2002 [DEBUG ] (smtpserver): Socket to <load
> balancer IP> closed remotely.
> java.net.SocketException: Connection reset by peer: Connection reset by
> peer
> at java.net.SocketInputStream.socketRead(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:90)
> at
> java.io.BufferedInputStream.fill(BufferedInputStream.java:186)
> at
> java.io.BufferedInputStream.read(BufferedInputStream.java:204)
> at java.io.DataInputStream.readLine(DataInputStream.java:449)
> at
> org.apache.james.smtpserver.SMTPHandler.handleConnection(SMTPHandler.java:163)
> at
>
>org.apache.avalon.cornerstone.blocks.connection.ConnectionRunner.run(Connection.java:163)
> Tue Apr 23 22:02:58 GMT 2002 [ERROR ] (smtpserver): Connection timeout
> on socket
>
> connections.log:
>
> Tue Apr 23 22:11:34 GMT 2002 [DEBUG ] (connections): Starting
> connection on Socket[addr=<load balancer IP>/<load balancer
> IP>,port=<source port>,localport=<james smtp port>]
> Tue Apr 23 22:11:34 GMT 2002 [DEBUG ] (connections): Ending connection
> on Socket[addr=<load balancer IP>/<load balancer IP>,port=<source
> port>,localport=<james smtp port>]
> Tue Apr 23 22:11:36 GMT 2002 [ERROR ] (connections): Exception
> accepting connection
> java.net.SocketException: Software caused connection abort
> at java.net.PlainSocketImpl.socketAccept(Native Method)
> at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:468)
> at java.net.ServerSocket.implAccept(ServerSocket.java:243)
> at java.net.ServerSocket.accept(ServerSocket.java:222)
> at
> org.apache.avalon.cornerstone.blocks.connection.Connection.run(Connection.java:93)
> at
>
>org.apache.avalon.excalibur.thread.impl.ExecutableRunnable.execute(ExecutableRunnable.java:47)
> at
> org.apache.avalon.excalibur.thread.impl.WorkerThread.run(WorkerThread.java:80)
> Tue Apr 23 22:11:38 GMT 2002 [DEBUG ] (connections): Starting
> connection on Socket[addr=<load balancer IP>/<load balancer
> IP>,port=<source port>,localport=<james smtp port>]
> Tue Apr 23 22:11:38 GMT 2002 [DEBUG ] (connections): Ending connection
> on Socket[addr=<load balancer IP>/<load balancer IP>,port=<source
> port>,localport=<james smtp port>]
> Tue Apr 23 22:11:40 GMT 2002 [ERROR ] (connections): Exception
> accepting connection
>
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