Slashdot Mirror

fadden writes: "I recently started blocking IP addresses in China and Korea that were sending me spam. Instead of a blanket ban, I only blocked the subnets from which spam was being sent. After my first week of scanning and banning, I wrote up a report on the effectiveness of the blocks." In related news, SSKennel adds that: "The U.S. Federal Trade Commission has discovered (prepare to be amazed!) that revealing your email address in chat rooms can get you spammed. It claims to have taken action against spammers who harvest email addresses and use them to send fraudulent spam." Shocker!

Saturated Subnet writes "Recently in Toledo, OH FBI agents and a local police task force raided 13 residence and seized 23 computers. Some users of the local cable broadband provider had uncapped their cable modems." It appears to be a smaller ISP, and the article says these 23 people cost them a quarter of a million bucks. Who has time to look at $10,800 worth of pr0n?

Brian Stretch writes: "The Code Red II worm was unleashed early this morning and appears to be very different than the original and far more dangerous. CR2 infected servers only attack servers within their Class A address block and their Class B address block in particular: since 9:11am EST I've logged 148 CR2 attack attempts, 89 of which are from within my Class B subnet, suggesting that only servers within Class A networks that were deliberately seeded are being attacked. The 24.x.x.x range is one of the hardest hit, and as before, it's folks with cable modems and DSL connections that are providing the most victims." Several @home customers have written about slowed service today, but they're definitely not alone.

sachsmachine explains: "I'm a student at a major university where the network admins are thinking of moving to a packet filtering system, one that would block non-university computers from connecting to machines on the student subnets. There will be a meeting to discuss the proposal on Tuesday, but to be fully prepared going in, I'd like to be sure what impacts the move would have. Some of the things that might be broken (depending on what ports get left open) are pretty clear -- remote logins of various sorts, file sharing, Web sharing, instant messaging, Napster and everything else P2P -- but are there any important/unusual/cool/academically useful applications whose ports we should lobby to protect?" By the nature of university (and corporate) rule making, once a policy is in place, it's much harder to dislodge or amend than it might be beforehand. Steve has listed a fair number of applications which could be tossed out by this; how would you suggest saving university bandwidth without losing them all? How would you convince a skeptical audience that remote access is not all of a piece?

fialar asks: "I have a machine (machine A) that provides an encrypted, private channel (VPN via vtun). It connects to Machine B and gives Machine B an IP address on Machine A's subnet (which is unused). I've added the proper arp command line (arp -i eth0 -sD eth0 pub), however Machine B cannot ping outside of Machine A's subnet. After a certain period of time, it can, but I am not sure why. Is there a way to set it up so that when the connection between Machine A and B happens, the proper rules are set up so that Machine B will be able to get out? IP Masquerading is not an option. I need Machine B to show up on Machine A's subnet."

David Hansen asks: "I want to see what problems other Slashdot users have had with @Home restricting their service. We all know that they block the SMB ports, and probably for good reason. But did you know that they won't let you access certain other machines on the @Home network? And why don't they mention any of this in their acceptable use policy? My mother and father are both @Home subscribers in the same city (different subnets). I have Linux boxes acting as firewalls in both places which cannot ping or otherwise contact each other. I can ping them both from an outside location. I discovered this and the SMB thing the hard way. What else doesn't @Home want us to do? Do other ISPs do this also? BTW, I can reach @Home users who are in other cities." I've noticed that ISPs have been filtering lots of ports in the event that users will put up servers. Do you feel that ISPs should make a list of ports that they filter available to their customers?

photozz asks: "We are on a large network (1000+ nodes) with a mix of everything, Wintel, Unix, Linux and Mac. Lately, we have been getting broadcast storms that kill the network. Our solution is to subnet everything with routers, thus killing broadcast trafic. BUT, this will limit Windows browsing on the network to each segment. Installing Brouters will just give us the same packet storm problems we had before. How can we stop broadcast trafic while enabling Netbios resolution acros routers?"

legana asks: "We are just about to install multiple cable modems at our office and we were wondering how to make the best use of them. What software/hardware is available that will allow us to share the modems across the network but still allow certain users priority (for uses such as video-conferencing, etc.)? Is it better to share all the modems across the entire network or break the network into subnets each with their own group of modems? Does connecting multiple modems to one computer really increase the bandwidth available?"

smkndrkn asks: "I'm looking to change our firewall config at work from a dual-homed host architecture to an OpenBSD based Screened Subnet Architecture, however I have a PPTP (yes I know it is horrible but our customer isn't changing to IPSec for another couple months )VPN that needs to work. I've looked at www.OpenBSD.org but cannot find much in the way of documentation ( other than the FAQ ). My current Linux firewall does this fine. I'm looking to have the Exterior router setup with Slackware Linux and the interior router setup with OpenBSD for more security ( and a diversity of architectures ). I'm a little worried that the PPTP connection will not work ( Does it filter GRE? )and that possibly I'll run into other issues. Just for some additional info I need the VPN to go through both routers to get to our internal network ( where the machines that use the connection are located ). Is there another way of doing this? Say have a machine on the perimeter network connect and then allow the machines to connect to that server, which would then route their traffic over the VPN? "

LRU wrote in to send us a link to netscan.org. This nifty site will check to see if a subnet is smurfable. Might actually useful for some of us.

the ISDN line is working. We moved to a different neighborhood just so we could get some bandwidth. Between ISDN line problems (courtesy of the mutants at the telco) and ISP problems, and router config problems (courtesy of everyone and their brother that looked at our router and failed miserably) it was a long painful journey. But a journey that has ended with a house with its own subnet and finally a phone line that doesn't need to be dialed out 24/7. Life is good. Gimme a beer, I've earned it.