April 2002 - WLUG - wlug.mailman3.com

Another interesting .signature...

by Stephen C. Daukas

"Volk" means "people". You can figure out the rest. "One World, One Web, One Program" - Microsoft Ad "Ein Reich, Ein Volk, Ein Fuhrer" - Adolf Hitler

April 3, 2002

Re: [Wlug] Problems dropping telnet sessions

by Jason Calvert

Sounds like a firewall problem. Just for fun you might try lowering your keepalive time to say 29 min, or even lower just for testing, and see if that helps. The default is 2 hours (7200 sec) or 14400 half sec on bsd) cat /proc/sys/net/ipv4/tcp_keepalive_time 7200 you can use sysctl or just echo the new value in echo 1740 > /proc/sys/net/ipv4/tcp_keepalive_time or sudo /sbin/sysctl -w net.ipv4.tcp_keepalive_time=1740 Anyone know if this works for clients as well as daemons? Jason On Tue, 2002-04-02 at 09:36, Simoncini, Matthew wrote: > Hello all, > > I recently traded in my Solaris 8 (x86) install for SuSE Linux 7.3 and now > am having problems keeping telnet sessions open for extended periods of > time. Let me give a little background on what I use this box for. > > Basically my linux box is used as a workstation for system monitoring. I > usually have 6 to 8 separate desktops which I use to separate our different > Unix environments (i.e. development, test, production ...). I may run HP > Openview client on one desktop to monitor alerts and keep telnet sessions > open on other desktops in order to quickly access a given server. > > Until recently I've been using Solaris 8 (x86) with no problems, but decided > I wanted to get comfortable with linux and prove to my boss that there are > many nice things we can do with linux that we can't do with Solaris. I > installed SuSe 7.3 (2.4.10 kernel) and since have had troubles keeping > telnet connections alive. What I mean by that is, when I leave the linux > workstation inactive for a period of time (let's say 30 minutes), my telnet > sessions are disconnected with the message "Connection closed by foreign > host". I can find no messages in /var/adm/messages (on the Solaris side) or > /var/log/messages (on the linux side). > > Anyone have this type of problem or more importantly, can someone point me > in the right direction? > > Thanks. > > Matthew > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

April 2, 2002

Re: [Wlug] Problems dropping telnet sessions

by Charles R. Anderson

Try ipchains -L too, since you might have an ipchains based firewall. On Tue, Apr 02, 2002 at 11:33:44AM -0500, Simoncini, Matthew wrote: Matthew.Simoncini> This is really quite interesting to me, so any input is very helpful. Maybe the TCP timers are different on Linux? They are in /proc/sys/net/ipv4/tcp*. Some docs for these variables are available here: http://www.linuxhq.com/kernel/v2.4/doc/networking/ip-sysctl.txt.html You might also want to look at the tcp(7) manual page where they also document the sysctls: man 7 tcp -- Charles R. Anderson <cra(a)wpi.edu> / http://angus.ind.wpi.edu/~cra/ PGP Key ID: 49BB5886 Fingerprint: EBA3 A106 7C93 FA07 8E15 3AC2 C367 A0F9 49BB 5886

April 2, 2002

RE: [Wlug] Problems dropping telnet sessions

by Simoncini, Matthew

I executed the iptables -L command and got the following output: Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination I'm not really that familiar with firewalls in linux, but I would assume that iptables is running without rules? I also noticed that it's not one particular host that bumps me out of telnet, but all connections and all hosts. The network folks don't know (or maybe they do) that I'm running linux on the network, but is there a way for them to periodically reset the port I'm using in the data closet? This is really quite interesting to me, so any input is very helpful. Thanks. -----Original Message----- From: Theo Van Dinter [mailto:felicity@kluge.net] Sent: Tuesday, April 02, 2002 11:11 AM To: wlug(a)mail.wlug.org Subject: Re: [Wlug] Problems dropping telnet sessions On Tue, Apr 02, 2002 at 09:36:00AM -0500, Simoncini, Matthew wrote: > Anyone have this type of problem or more importantly, can someone point me > in the right direction? My first two thoughts are: iptables times out your connection for some reason, or the remote side has an autologout value set. Is there a firewall setup on your box? You can do "iptables -L" to find out. As for autologout, I would think this would have affected you before, but it's something to rule out anyway. What shell are you using on the remote machines? If it's a csh variant, run "echo $autologout" and see what it comes back with. If it comes back with a defined non-0 value, that is a likely cause of your problem. Run "set autologout=0" and see if that fixes your problem. -- Randomly Generated Tagline: "Note that if I can get you to \"su and say\" something just by asking, you have a very serious security problem on your system and you should look into it." (By Paul Vixie, vixie-cron 3.0.1 installation notes) _______________________________________________ Wlug mailing list Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug

April 2, 2002

Re: [Wlug] RBL access

by Theo Van Dinter

On Tue, Apr 02, 2002 at 10:57:42AM -0500, Chuck Homic wrote: > BTW, for the curious, my daily haul of junk mail varies from 20 to 40 > messages. Can anyone beat that? I'm currently at 49 since midnight on April 1st. This isn't counting the spams rejected at the SMTP level that I never see. -- Randomly Generated Tagline: "Logic is a systematic method of coming to the wrong conclusion with confidence." - Sinclair on Babylon 5

April 2, 2002

Re: [Wlug] Problems dropping telnet sessions

by Theo Van Dinter

On Tue, Apr 02, 2002 at 09:36:00AM -0500, Simoncini, Matthew wrote: > Anyone have this type of problem or more importantly, can someone point me > in the right direction? My first two thoughts are: iptables times out your connection for some reason, or the remote side has an autologout value set. Is there a firewall setup on your box? You can do "iptables -L" to find out. As for autologout, I would think this would have affected you before, but it's something to rule out anyway. What shell are you using on the remote machines? If it's a csh variant, run "echo $autologout" and see what it comes back with. If it comes back with a defined non-0 value, that is a likely cause of your problem. Run "set autologout=0" and see if that fixes your problem. -- Randomly Generated Tagline: "Note that if I can get you to \"su and say\" something just by asking, you have a very serious security problem on your system and you should look into it." (By Paul Vixie, vixie-cron 3.0.1 installation notes)

April 2, 2002

Re: [Wlug] RBL access

by Adam ＠ Oak

Only my hotmail account beats that ;-). Of course, that's what its there for... -Adam > BTW, for the curious, my daily haul of junk mail varies from 20 to 40 > messages. Can anyone beat that? "lingua machinationis creo, ergo sum" _____________________________________________ Adam Keck The Mathworks 508-647-7298 Natick, Ma www.mathworks.com FreeNIX/Backup/Unix Administrator _____________________________________________

April 2, 2002

Re: [Wlug] RBL access

by Theo Van Dinter

On Tue, Apr 02, 2002 at 10:57:42AM -0500, Chuck Homic wrote: > I'm getting quite a lot of crap email these days, ever since ORBS/ORBL & > Co. disappeared, and MAPS went to a fee-based service. (I'm really not > planning to pay $200/yr for a single blackhole list.) I was never really > crazy about MAPS to begin with, because they tried too hard to be "fair." MAPS is still free for non-commercial use. There are many others out there. > Anyway, is anyone using (or know of) a freely-queriable RBL? Although > it's fun to upgrade the keyword filter, it would be easier if I only had > to do it for exceptions. > > BTW, for the curious, my daily haul of junk mail varies from 20 to 40 > messages. Can anyone beat that? check out: http://www.kluge.net/mailfiltering/ I've been writing up most of what I do on my machine. It's partially written for my users and partially written for other people who want to find out about mail filtering. At a minimum, I have a listing of the RBLs that I specifically use. There are more out there. My main suggestion to you is: get SpamAssassin. For anything that gets through your MTA, it'll clear up your inbox. -- Randomly Generated Tagline: "Minix is one of the reasons I decided microkernels are bad. VMS is the reason I decided VMS is bad." - Linus Torvalds

April 2, 2002

Re: [Wlug] RBL access

by Charles R. Anderson

Use Spamassassin. Seriously. It works. Very well. http://www.spamassassin.org/ -- Charles R. Anderson <cra(a)wpi.edu> / http://angus.ind.wpi.edu/~cra/ PGP Key ID: 49BB5886 Fingerprint: EBA3 A106 7C93 FA07 8E15 3AC2 C367 A0F9 49BB 5886

April 2, 2002

RBL access

by Chuck Homic

Hey, guys. I'm getting quite a lot of crap email these days, ever since ORBS/ORBL & Co. disappeared, and MAPS went to a fee-based service. (I'm really not planning to pay $200/yr for a single blackhole list.) I was never really crazy about MAPS to begin with, because they tried too hard to be "fair." ;) ORBS was hyper-aggressive, and rocked. (About 80% of my crap email was filtered by ORBS, and I had special pre-RBL filters that extracted mail from friends using bad ISP's with open relays.) Anyway, is anyone using (or know of) a freely-queriable RBL? Although it's fun to upgrade the keyword filter, it would be easier if I only had to do it for exceptions. BTW, for the curious, my daily haul of junk mail varies from 20 to 40 messages. Can anyone beat that? -Chuck

April 2, 2002