openSUSE Security March 2000

security@lists.opensuse.org

93 participants
70 discussions

sendmail -- sender domain must resolve
by Chrissy LeMaire 22 Mar '00

22 Mar '00

Hey All, I'm running sendmail 8.9.3 and pretty much left everything default. The spam stoppers are in full effect.. I have a question about the following: Mar 20 14:39:25 xxx sendmail[18726]: OAA18726: ruleset=check_mail, arg1=<xxx(a)bebe.com>, relay=[111.111.111.111], reject=451 <xxx(a)bebe.com>... Sender domain must resolve So i do a bit of digging: # nslookup > bebe.com Server: ns.server.com Address: ip.addy.here *** ns.server.com can't find bebe.com: Non-existent host/domain > set type=mx > bebe.com Server: ns.server.com Address: ipaddyhere Non-authoritative answer: bebe.com preference = 0, mail exchanger = bebe-mail.bebe.com Authoritative answers can be found from: bebe.com nameserver = AUTH02.NS.UU.NET bebe.com nameserver = bebe-ns.bebe.com bebe.com nameserver = BEBE-NS2.bebe.com bebe-mail.bebe.com internet address = 208.240.224.197 AUTH02.NS.UU.NET internet address = 198.6.1.82 bebe-ns.bebe.com internet address = 208.240.224.225 BEBE-NS2.bebe.com internet address = 208.240.224.210 By looking at this.. I concluded that MX records aren't looked at when deciding if a domain resolves or not. So.. I do the some testing with hospitalforms.com (which doesnt resolve but has an MX record) and it worked.. So. Am I right when I assume that bebe.com's ns servers were most likely down for a period of time? Auth02.ns.uu.net is huge.. and 3 nameservers all go down at the same time? This doesnt seem right. Any suggestions?

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RE: [suse-security] sendmail -- sender domain must resolve
by Wood, Alan 22 Mar '00

22 Mar '00

Chrissy, I expect that you will always get this response, it is common for the domain not to have an IP address, after all, which machine should it tell you about? If you tried www.bebe.com, you will probably get an IP address as that will translate to an actual machine. Sendmail will always assume MX records as these are all that is relevant to it. Why should sendmail worry about the web or FTP address ;-) Alan > ---------- > From: Chrissy LeMaire[SMTP:chrissy@netnerds.net] > Sent: 21 March 2000 18:06 > To: suse-security(a)suse.com > Subject: [suse-security] sendmail -- sender domain must resolve > > Hey All, > I'm running sendmail 8.9.3 and pretty much left everything default. The > spam stoppers are in full effect.. > > I have a question about the following: > > Mar 20 14:39:25 xxx sendmail[18726]: OAA18726: ruleset=check_mail, > arg1=<xxx(a)bebe.com>, relay=[111.111.111.111], reject=451 <xxx(a)bebe.com>... > > Sender domain must resolve > > So i do a bit of digging: > > # nslookup > > > bebe.com > Server: ns.server.com > Address: ip.addy.here > > *** ns.server.com can't find bebe.com: Non-existent host/domain > > > set type=mx > > bebe.com > Server: ns.server.com > Address: ipaddyhere > > Non-authoritative answer: > bebe.com preference = 0, mail exchanger = bebe-mail.bebe.com > > Authoritative answers can be found from: > bebe.com nameserver = AUTH02.NS.UU.NET > bebe.com nameserver = bebe-ns.bebe.com > bebe.com nameserver = BEBE-NS2.bebe.com > bebe-mail.bebe.com internet address = 208.240.224.197 > AUTH02.NS.UU.NET internet address = 198.6.1.82 > bebe-ns.bebe.com internet address = 208.240.224.225 > BEBE-NS2.bebe.com internet address = 208.240.224.210 > > > By looking at this.. I concluded that MX records aren't looked at when > deciding if a domain resolves or not. So.. I do the some testing with > hospitalforms.com (which doesnt resolve but has an MX record) and it > worked.. > > So. Am I right when I assume that bebe.com's ns servers were most likely > down for a period of time? > Auth02.ns.uu.net is huge.. and 3 nameservers all go down at the same time? > > This doesnt seem right. > > Any suggestions? > > --------------------------------------------------------------------- > To unsubscribe, e-mail: suse-security-unsubscribe(a)suse.com > For additional commands, e-mail: suse-security-help(a)suse.com >

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RE: [suse-security] SSH2 pointers
by Mr. M 19 Mar '00

19 Mar '00

L. Sassaman wrote: > SSH2 is free for non-commercial use. > This is not exactly true. It would depend on your definition of commercial use. If you read the licensing of SSH2 you'll discover that they redefined what they consider to be commercial use. The license states: "NON-COMMERCIAL USE shall mean the following uses of the SOFTWARE: a) any use done outside and without connection to a commercial organization and commercial activity, b) use related to leisure time activities by private individuals, including hobbies, games, etc. provided however that such use is not commenced with commercial companies. Uses not considered as NON-COMMERCIAL USE include, but are not limited to: a) any use where commercial activity is involved and where the use in any way, directly or indirectly, aims at monetary or other commercial benefit, b) any use that takes place in commercial, governmental, military, or similar organizations and where a salary or similar monetary compensation is paid, unless the use can be considered to be EDUCATIONAL USE or is purely for charity." jonathan stated they he wished to use SSH2 to get files from work. This activity would violate the SSH2 agreement. Mario

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ssh w/ chroot
by Security Webmaster OKDesign oHG 19 Mar '00

19 Mar '00

Hi, I know, this topic was already discussed several times. Can anyone point me to an URL from where I can get infos about how to use chroot for ssh-connections ? TIA --- Stephan

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SSH2 pointers
by jonathan 19 Mar '00

19 Mar '00

I just downloaded ssh2 and installed it, and I am looking for some pointers from folks who have set it up in the past. I did not use the rpm from the suse, I got it from ssh.org and compiled local. I would rather learn from someone else getting cracked than learn the hard way. I am using SuSE6.3, kernel 2.2.13. I want to be able to have it running on the firewall and file server (2 separate machines), so I can get to my files from work via the internet. Any and all suggestions welcomed. TIA

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[suse-security] chroot
by Timo Schulz 18 Mar '00

18 Mar '00

The harden_suse script says the following: "put every daemon in chroot and try to run them unpriviliged" Does anybody know where I can get more infos about the chroot program and running daemons unprivilged? ( I looked at the manpage and the info text, but they werent't really informations about this ) Thanks. -- Two-a-Day at joesixpack.net www.freenet.de/joesixpack keyid BF3DF9B4

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Opening the firewall for playing games
by Frank Hart 17 Mar '00

17 Mar '00

Hi all, What is the most secure way to open the firewall for playing games on Heat.net? They request access to several ports, so I've added the IP adresses of Heat.net to FW_TRUSTED_NETS="194.176.220.0/24 208.213.56.0/24" and they have access to all UDP ports. Is there a way to limit this access? -- Frank Hart - mailto:frhart@home.nl SuSE Linux - Kernel 2.2.14 on a i586 100 Mhz with 24 Mb RAM -- "What is wanted is not the will to believe, but the will to find out, which is the exact opposite." -- Bertrand Russell, "Skeptical_Essays", 1928

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Re: [suse-security] Understanding IP-Forwarding with ipfwadm
by Grant DuVall 17 Mar '00

17 Mar '00

Your problem may be the order in which your place the rules. Try putting the last line in first. Deny everyone first then poke holes in it. Most firewalls have some sort of precedence. Thanks, Grant DuVall medibuy.com Network Administrator

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Firewall and Proxy Server HOWTO
by Sloate, Arthur 16 Mar '00

16 Mar '00

I am attempting to follow the 'Firewall and Proxy Server HOWTO' written by Mark Grennan, but have been running into a problem in section 6.4. When pinging the outside address of the firewall from a computer on the LAN, it works. At this point of the test process, it shouldn't. IP Forwarding is turned off, and I have turned off IP Masquerading. Can anyone provide me with some guidance? Cheers, Art Sloate

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RE: [suse-security] *WANTED: ipchains guru*
by KULISHdotCOM 16 Mar '00

16 Mar '00

Guess I should have made that a little clearer ;). I am wanting to figure this out from scratch. I am trying to break out of the *Windows Only* frame that I am in concerning security that I recommend to clients. Right now, I recommend Raptor, Firewall-1, or MS Proxy depending upon the situation. Being able to configure ipchains from scratch would be a great solution for clients on a limited budget. Thanks for the reply though! CK -----Original Message----- From: robert(a)texas.net [mailto:robert@texas.net]On Behalf Of Robert C. Paulsen, Jr. Sent: Tuesday, March 14, 2000 8:04 PM To: KULISHdotCOM Subject: Re: [suse-security] *WANTED: ipchains guru* KULISHdotCOM wrote: > > Looking for someone to take a look at my ipchains script. I don't want to > post it on the list as it is kind of long. A little background is in order. > > I want to setup an ipchains firewall to do the following: > > Deny everythind that is not explicitly allowed. > > I have a server sitting behind it that will host pop3, smtp, www, and ftp so > I will need to forward all these ports. > > I want to allow everyone on the local network to ANYTHING out on the > internet. > > I want to log any denials and protect against IP spoofing (and anything else > that might be dangerous). > > If anyone is willing to help, I will send them my annotated script to take a > look at. I do realize that some things are missing (probably the stuff I > need help on). > > I have read all the HOW-TOs that I can find but something isn't clicking. > I would start here: ftp://ftp.suse.com/pub/suse/i386/update/6.3/sec1/firewals.rpm It will take a little thought and work to get it set up, but not as much as trying to do the whole thing yourself. -- ____________________________________________________________________ Robert Paulsen If my return address contains "ZAP." please remove it. Sorry for the inconvenience but the unsolicited email is getting out of control.

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openSUSE Security March 2000