ftpd login takes forever to start... 1

[darken9999]

I'm running Redhat 7.0 w/ wu-ftpd 2.6.1-16. The system is a PII 450, with 128MB RAM. It's serving http requests for webmail (which doesn't get used much at all), e-mail, telnet, and ftp.

The system does seem a little taxed, but I'm just chalking it up to trying to serve too much from too old a box. The problem I'm curious about is the ftpd, however. All requests take a little bit, but ftp is rediculous. A connection is made quickly, but the login prompt doesn't appear for a seeminly random length of time afterward. Sometimes it's immediate, and sometimes it's twenty seconds later. It just doesn't seem like it should take that long, considering what little the server is doing otherwise.

In xinetd, I put the nice variable for ftpd back to zero, but that didn't seem to change anything. I dunno. Any suggestions to fix it, or at least a little insight to what's going on?

Thanks,
Andre

 

[marsd]

How about telnet? Same problem?
If so..check your reverse zones.
How many users for email? Do you have shell
accounts? Run top for a while (this will eat resources)
and take a look at mem use and processor overhead.
If you are consistently over 1.0(cpu util) some tasks
will have to wait for their timeslice. This will slow things down. Are you swapping? This will really slow
things down..with 128 megs RAM you should not be.
I have ussed a 32 mb 586 for verything but ftp and
it is fairly responsive, with over 50 mail users.
(closed relay)
Traffic shaping: in periods of high traffic with
some traffic shaping schemes, some types of ip traffic
can be adversely affected.
(cisco fair-queue for example and FIFO)

 

[willywonka]

That other response may be making this all too complicated. Try this: on your Redhat 7.1 machine (the one you're ftp'ing into) put an
entry in the /etc/hosts file for the machine you are ftp'ing FROM. Give it the IP address and host name. That usually causes ftp and telnet to respond immediately.

That little trick has solved many a connection headache. I believe the problem stems from the ftp server host doing due dilligence with authentication and takes a long time to determine that the requesting host is NOT denied. It may time out trying a DNS or NIS lookup.

If you understand the /etc/nsswitch.conf file, check there. Perhaps you have DNS or NIS listed when you don't actually use them on your network. That can hang a verification/authentication query.

 

[darken9999]

Thank you both for the help. It turned out to be a problem with xinetd's logging, but I wouldn't have figured that out without your help.
I'm curious now, however. Is there a way to stop swapping? I've never even considered trying.

Andre

 

[marsd]

No. Linux is very fast because it minimalizes the use
of virtual memory(disk). If you WERE swapping that would
be something that needs to be addressed by finding out
where the memhog was. Otherwise having that disk space to page to is a necessity.

WW:
DNS is the de facto means of resolving host names on the internet not localhost files.
DNS was invented to get away from the kind of situation you are describing. It is better to fix a potential
DNS issue, than avoid it by adding a local host designator.
Some services are not really compatible with file based
lookups(smtp mta's for one). It is not advisable to have several different resolution schemes in place if one
will suffice.
The post was intended as a checklist of things that could possibly be wrong, and to check, not a serious suggestion of multiple problems.