Subject: ftpd mbuf leak [1059]

From: Donn Cave <[email-masked]>
Date: Fri, 06 Jan 1995 14:44:56 -0800 (PST)

[I'm on since Fri. afternoon PST and of course have missed prior
 correspondence; apologies if this is an old tired topic.]

In the last couple of weeks we have had serious problems with our
anonymous ftp service gradually using up enormous amounts of network
buffer memory, as shown in netstat -m.

The culprits seem to be connecting from serial IP (SLIP or PPP) services.
I think they're failing to complete transactions, and leaving the connection
in CLOSE_WAIT.

During this time we have run the service from
  1. RISC Ultrix 4.2a standard issue ftpd
  2. Alpha OSF/1 3.0, wu ftpd.
  3. Alpha OSF/1 3.0 standard issue ftpd

All suffer from some variation on the syndrome.  Our Alpha now claims to
have allocated 22 Mb for network buffers, and I'm not sure I believe that.
There are 231 outstanding connections to port 21, 101 in CLOSE_WAIT.
Those CLOSE_WAITers will eventually drop if I kill all the old ftpd
sessions, but the reported allocation keeps climbing.

Anyone seen anything like it, have any ideas?

	Donn Cave, University Computing Services, University of Washington
	[email-masked]