- WLUG - wlug.mailman3.com

Re: [Wlug] meeting next week?

by Andy Stewart

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Eric Stein wrote: > Unfortunately I'll have gone home by the 10th. Oh well, you guys will > still be here next year, right? > > Eric HI Eric, We meet every month, even in the summer. We'll keep meeting until nobody shows up any more. :-) Sure, we'll be around next year (I presume you mean September). See ya later, Andy - -- Andy Stewart, Founder Worcester Linux Users' Group Worcester, MA, USA http://www.wlug.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFETvSZHl0iXDssISsRAuU/AJ9j/iysKMUSRkXhRPUSdPLIXIJ/1ACdGjtD mS0RYQZhbrzvQnZLf3ddgm8= =CLMD -----END PGP SIGNATURE-----

April 26, 2006

Re: [Wlug] meeting next week?

by Eric Stein

Unfortunately I'll have gone home by the 10th. Oh well, you guys will still be here next year, right? Eric Andy Stewart wrote: > Hi Eric et al, > > The website says May 10th (but I haven't yet updated the home page). > > There is currently no scheduled topic for the May meeting. > > We do have a topic for the June meeting (a rep from Sybase will give the > talk). I have lots of goodies from Sybase to give away at that meeting > (thanks Sybase!). > > I'll try to get the website updated within the next day. > > Andy > > -- > Andy Stewart, Founder > Worcester Linux Users' Group > Worcester, MA, USA > http://www.wlug.org -- Eric Stein WPI CS 2009 Treasurer, Student Pugwash

April 25, 2006

Re: [Wlug] Mail servers, Comcast, and spam

by Andy Stewart

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 HI all, Comcast appears unwilling to whitelist the Town email domain since this is quite easily spoofed by spam generators. The Town is considering using port forwarding on their firewall to reach the mail server. The Town is unwilling to put the mail server on or outside of the firewall, claiming that the risk level is too high for them to support. Later, Andy - -- Andy Stewart, Founder Worcester Linux Users' Group Worcester, MA, USA http://www.wlug.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFETpgZHl0iXDssISsRArvsAJ95z2vFXZiZVK7eu/A/zBwxgBVWIQCfebM/ gDQBjl+MCVf9/PE68lIpEmE= =Sfj+ -----END PGP SIGNATURE-----

April 25, 2006

Re: [Wlug] meeting next week?

by Andy Stewart

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Eric Stein wrote: > Hi all, > > I'm only writing to ask whether or not there will be a meeting held on > the 3rd and if we have a topic. Thanks. > Hi Eric et al, The website says May 10th (but I haven't yet updated the home page). There is currently no scheduled topic for the May meeting. We do have a topic for the June meeting (a rep from Sybase will give the talk). I have lots of goodies from Sybase to give away at that meeting (thanks Sybase!). I'll try to get the website updated within the next day. Andy - -- Andy Stewart, Founder Worcester Linux Users' Group Worcester, MA, USA http://www.wlug.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFETpMPHl0iXDssISsRAiwvAJ9orMhoVudi2hzxubaUkdYLcWYWlQCfZvvC Y60GVTZjcDaF9dDJFefrThs= =aG8C -----END PGP SIGNATURE-----

April 25, 2006

Re: [Wlug] Mail servers, Comcast, and spam

by Bill Mills-Curran

On Tue, Apr 25, 2006 at 11:58:13AM -0400, Theo Van Dinter wrote: > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug > Date: Tue, 25 Apr 2006 12:03:30 -0400 > Subject: > Content-Description: ATT10815498.txt > On Tue, Apr 25, 2006 at 09:36:20AM -0400, Chuck Anderson wrote: > > I'll add that WPI uses separate servers for receiving and sending SMTP > > connections. The sending servers are not in any DNS MX records, so > > any site using "spam blocking" tactics that require the sending SMTP > > server to be listed as an MX would block WPI email. > > Most mid-to-large organizations will do this as well. It would be > complete stupidity for a receiver to not accept mail from a server whose > domain MX record doesn't include that server -- they'd be blocking a vast > majority of domains. What's more plausible is that the receiver is blocking > mails from domains lacking an MX record, but even that's going to cause false > positives (FPs) on a large amount of domains. > > The usual thing that happens is that receivers block mails where the host > part of the email address (to the right of the @) has no A or MX record > at all. Since to the receiver it looks like that host doesn't exist, > why accept mail from it? > > ie: > > HELO nonexistant.example.com > > where, typically, nonexistant is a host behind a firewall, but isn't in the > external DNS zone. Usually all hosts behind a firewall send to a relay > gateway which masquerades the headers and envelope so that the receiving > server sees an externally available name. ie: > > nonexistant.example.com (helo nonexistant ...) -> > relay.example.com (helo example.com) -> > your-server > > so when your-server gets the mail, it looks up "example.com" and finds A/MX > records, so accepts the mail. > > -- > Randomly Generated Tagline: > "Many people equate the word 'daemon' with the word 'demon,' implying some > kind of Satanic connection between UNIX and the underworld." - Evi Nemeth I'm wondering whether it might actually be a reverse lookup issue. I recently had to opt into a static IP at my web & mail services provider so that reverse lookups would work. AOL has started blocking email from senders that don't have a valid PTR record. If the mail server is behind a firewall, this _could_ be the issue. I use a mail server at home behind a firewall, but I don't send directly to the recipient -- I use the "smart host" feature of sendmail. The "masquerade_as" feature might be what they need. The trick is to make the smtp server look as though it's using the "external" hostname and IP address. I'm just guessing, though. :-) Bill

April 25, 2006

meeting next week?

by Eric Stein

Hi all, I'm only writing to ask whether or not there will be a meeting held on the 3rd and if we have a topic. Thanks. -- Eric Stein WPI CS 2009 Treasurer, Student Pugwash

April 25, 2006

Re: [Wlug] Mail servers, Comcast, and spam

by Theo Van Dinter

On Tue, Apr 25, 2006 at 09:36:20AM -0400, Chuck Anderson wrote: > I'll add that WPI uses separate servers for receiving and sending SMTP > connections. The sending servers are not in any DNS MX records, so > any site using "spam blocking" tactics that require the sending SMTP > server to be listed as an MX would block WPI email. Most mid-to-large organizations will do this as well. It would be complete stupidity for a receiver to not accept mail from a server whose domain MX record doesn't include that server -- they'd be blocking a vast majority of domains. What's more plausible is that the receiver is blocking mails from domains lacking an MX record, but even that's going to cause false positives (FPs) on a large amount of domains. The usual thing that happens is that receivers block mails where the host part of the email address (to the right of the @) has no A or MX record at all. Since to the receiver it looks like that host doesn't exist, why accept mail from it? ie: HELO nonexistant.example.com where, typically, nonexistant is a host behind a firewall, but isn't in the external DNS zone. Usually all hosts behind a firewall send to a relay gateway which masquerades the headers and envelope so that the receiving server sees an externally available name. ie: nonexistant.example.com (helo nonexistant ...) -> relay.example.com (helo example.com) -> your-server so when your-server gets the mail, it looks up "example.com" and finds A/MX records, so accepts the mail. -- Randomly Generated Tagline: "Many people equate the word 'daemon' with the word 'demon,' implying some kind of Satanic connection between UNIX and the underworld." - Evi Nemeth

April 25, 2006

Re: [Wlug] Mail servers, Comcast, and spam

by Brian J. Conway

On Tue, 25 Apr 2006, Stephen Ketcham wrote: > Then this isn't the full Comcast story, because I just received your > mail on a comcast.net account. > Same. Any specifics on the bounce error they're getting? I know Comcast, like many providers, will refused SMTP connections that originate from what it or its blacklist consider dynamic IP ranges (cable, DSL, etc), so to get around it I have to relay any mail I send to Comcast addresses through my ISP's mail server (adding "comcast.net smtp:my.isps.mailserver.com" to /etc/postfix/transport or /etc/mail/mailertable for Postfix and Sendmail, respectively). Of course, I'd imagine Comcast distinguishes business class customers from standard home connections, but any more info on the error could be helpful. Brian J. Conway bconway(at)alum.wpi.edu "LINUX is obsolete" - Andrew S. Tanenbaum, creator of Minix - Jan 29, 1992

April 25, 2006

Re: [Wlug] Mail servers, Comcast, and spam

by Stephen Ketcham

Then this isn't the full Comcast story, because I just received your mail on a comcast.net account. Steve On Apr 25, 2006, at 9:36 AM, Chuck Anderson wrote: > On Tue, Apr 25, 2006 at 06:52:32AM -0400, Eric Martin wrote: >> this is a M$ exchange server with an smtp connector. When I write an >> email, the smtp connector stamps it's id on my email outbound to the >> comcast servers. See where this is going? We don't want >> exhange.local.domain to be an mx record for my domain, it doesn't >> even >> face the internet. By this solution that Comcast is using, all email >> from local.domain would be bounced. > > I'll add that WPI uses separate servers for receiving and sending SMTP > connections. The sending servers are not in any DNS MX records, so > any site using "spam blocking" tactics that require the sending SMTP > server to be listed as an MX would block WPI email. > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug

April 25, 2006

Re: [Wlug] Mail servers, Comcast, and spam

by Chuck Anderson

On Tue, Apr 25, 2006 at 06:52:32AM -0400, Eric Martin wrote: > this is a M$ exchange server with an smtp connector. When I write an > email, the smtp connector stamps it's id on my email outbound to the > comcast servers. See where this is going? We don't want > exhange.local.domain to be an mx record for my domain, it doesn't even > face the internet. By this solution that Comcast is using, all email > from local.domain would be bounced. I'll add that WPI uses separate servers for receiving and sending SMTP connections. The sending servers are not in any DNS MX records, so any site using "spam blocking" tactics that require the sending SMTP server to be listed as an MX would block WPI email.

April 25, 2006