telnet or ftp is abnormal

xuyong · November 9, 2009, 7:43am

it’s very strange that the telnet or ftp service becomes very slow sometimes,but when you reboot the system it restores to normal condition.

maschoen · November 9, 2009, 4:29pm

I would check pidin and hogs to see if maybe something of higher priority is accumulating. If This is not the case, then I agree, it is very strange. I’ve noticed on two systems I have directly connected that telnet’ing from one to the other takes a surprising long time to get started. Once it does all is ok, but shouldn’t it just take the blink of an eye?

Tim · November 9, 2009, 5:51pm

I usually only experience slowdowns if you are using DNS name lookup and the DNS is slow to respond. For that reason I almost NEVER enable DNS unless I absolutely need it for something.

BTW, even if you are telnetting/ftping via IP address (and not name) and you have DNS enabled it can take a long time to connect if the DNS server is slow to respond.

Tim

maschoen · November 9, 2009, 6:28pm

Thanks Tim. I hadn’t thought of that before. I think I’m bypassing DNS because my /etc/hosts file is setup but I’ll check the next time I try this.

Mitchell

Tim · November 9, 2009, 7:39pm

Mitchell,

Don’t you mean in /etc/net.cfg? That’s where I specify a nameserver IP address for DNS lookup. Can it also be done in /etc/hosts?

The easiest way to see this problem is with ping.

Set up a nameserver/DNS. Then start io-net. Then with no cable connected start pinging yourself. It will take a long time to get the first response back even though you specify your own IP address and no DNS is needed! Then stop io-net, delete the nameserver, restart io-net and ping yourself again. This time you get instant response from the ping command.

Tim

maschoen · November 10, 2009, 12:36am

Well you may be onto something here. In the good old days, you put a statement in /etc/resolv.conf that said look at the local hosts file first, and it did.

/etc/net.cfg I believe is part of QNX’s newer QNX 6 implementation that is modified (usually) by their Photon network config program. I think that is where my problem is now. I don’t know how the older “Unix” way of doing things interacts with the newer way. I’ll have to look at the docs, darn. I’ll try your suggestion.

Thanks,