search for: backscatter

...nd. I run a few sendmail servers that run MailScanner/Spamassassin/sendmail (current versions) on Centos 5.4 and Centos 4.8 These boxes accept mail for a large number of domains (6000+) scan the mail removing spam and then forward the ham to another server for delivery. I am attempting to stop any backscatter that these servers cause by only accepting mail for specific users at domain or for domains with a catch-all account. I currently use /etc/mail/access.db as the access map for the domains, but this allows all mail to be accepted for the domain before the attempting to send it on for final delivery...

Hi all, I've had to deal with a sudden surge of backscatter email lately. Would anyone be able to suggest to solutions that worked for them regarding this problem? We are using Scalix 11 as our email platform. It uses Sendmail MTA for those who may not be familiar. Thanks, Matt -- Stand before it and there is no beginning. Follow it and there is no end...

Robert Schetterer <robert at schetterer.org> writes: >> Anyway, why use lmtp over lda ? > > i.e avoid backscatter by overquota A clarification on this: backscatter (or rather, ambiguous NDR notices that claim many users are over quota rather than just one) is a result of a local mailer that support multiple recipient delivery in one invocation, but can only return one result code to the MTA. Since Dovecot...

I've received a bunch of these blackberry backscatter messages over the past week and have been unable to determine which list user is the cause of this. Whoever is forwarding your email to the blackberry address below, please fix the situation. It's becoming really annoying receiving these backscatter bounces that give no clue as to what the na...

I'm using Dovecot LDA with Exim. I'm also using Dictionary Quotas in a MySQL database. I want to avoid backscatter completely, so I set "quota_full_tempfail = yes" and handle quota checking in the Exim RCPT ACL during the SMTP session. The problem lies in the case where a user's account is nearly full. Smaller messages will continue to come through, but a larger message would get queued for retr...

Out of curiosity would it be possible to configure dovecot in such a way that if a message had been accepted by postfix because it couldn't check quota the message was delivered anyway, despite being over quota? I'd much rather that then risk backscatter. (I used to have quotas, but with the size of disks I've found it easier to simply have a "clue bat?approach and a reasonable max-message size. When a user gets "too much?mail ask them to purge their older mails with attachments. Granted, that's probably less workable than quota...

How can I disable mail delivery for a user yet still allow access to their mailbox from another account which their mail is shared to? If I put them in a userdb which has "deny = yes" that just disables their ability to login, yes? And they would still have mail delivered. I want to disable their ability to login AND bounce all mail delivered to them, preferably solely through dovecot

...h are increasingly making rounds. With a working local delivery these will just feed spamassassin or rspamd and all is well. And may be the occasional poor Exchange customer's email is delivered, too. With Dovecot 2.3.4.1 and 2.3.5 dovecot-lda and lmtp these will generate bounces that lead to backscatter spam: postfix/pipe[22438]: D8C5E35C2600: to=<redacted at redacted>, relay=dovecot, delay=0.22, delays=0.14/0.01/0/0.08, dsn=5.3.0, status=bounced (command line usage error. Command output: lda: Fatal: Invalid -f parameter: Invalid character in localpart ) postfix/cleanup[22433]: 0D95435C25EF...

...urden of keep the SMTP session with the client open until the mail is finally stored? that don't scale! Sieve is all about policy. A 5xx reject would let the sending server know the message could not be delivered due a failure. (ie: user policy rejection, without receiving MTA generating NDR backscatter). I would rather not just accept it and the message disappear into ether without the sender receiving any notification of why. -- Robert inoc.net!rblayzor http://inoc.net/

...atest after the RCPT TO command, and at this time the milter, independent of what software you use, has no information about email header or content. Rejecting a mail AFTER the DATA command (when the content becomes available) was discouraged because of incorrect behaving MTAs. (e.g. generating backscatter, or even treating the mail as successfully sent) Maybe, and I really hope so, this problem no longer exists. I will immediately reconfigure my mail system, if rejecting mails after DATA will be safe and reliable nowadays. /andreas

...ts. If dspam fails, the mail >> is dumped, the LDA returns exit code 75, and the MTA will probably >> issue a bounce Email to the sender. > > which would be OK, if "never loose email contents" means "no message is > discarded silently". no, it is not OK to backscatter because the spamfilter fails realize that 99% auf junk is using forged senders recently i got each day some hundret such bounces from mailservers configured by fools reply to spam with forged senders and if i could i would have gone out for beat every responsible admin straight in the face ---...

Am 11.06.2020 um 19:15 schrieb Ralph Seichter: > Generating backscatter is definitely not a good move, and it is even > prone to punish yourself. Better to reject the offending message with > a 5xx status code and some explanatory text or the URL. > > The various tests required to come to a decision about accepting or > rejecting the message can be exec...

...i, I successfully configured dovecot using virtual users (and LDAP/AD). deliver is the LDA and verifies if the user exists (as recommended in the WIKI). However, the howtos in the Wiki say *nothing* about the case that the recipients should be verified *before* receiving the messages (prevent backscatter, ...). All configurations in the dovecot-Wiki (postfix and exim) just accept the mails and pass them to deliver. Also, all howtos which I found on the web. If the user does not exist, the mail is bounced because the mail was already accepted by the MTA. Nowadays this is an unacceptable configur...

...lways a bad thing - you > want the authoritative receiver to reject at the smtp level instead of > accepting at all. I agree, it is wrongful behavior to accept something which later you discover you can not deliver. I would call it bad MX setup, as you are making yourself potential source of backscatter (which though is not as much exploited yet as open relays, but still is bad setup). If you set backup MX based on postfix, there is relay_recipients you have to specify, which lists all e-mail addresses that are legitimate on primary MX. Nothing else is being accepted by default, thus secondary MX...

...latest after the RCPT TO command [...] Can you name examples? I have never used a milter so restricted, nor have I seen one being used. > Rejecting a mail AFTER the DATA command (when the content becomes > available) was discouraged because of incorrect behaving > MTAs. (e.g. generating backscatter, or even treating the mail as > successfully sent) Again I am stumped by what you write. SMTP rejection does not generate backscatter. Frankly, I see no use in discussing broken MTAs or milters, real or imagined. Using milter-regex and other milters with Postfix works fine as I described it. Wh...

Hi all, I'm working with radar remote sensing data and want to measure the height of 3d spikes created by backscatter from bright objects. My thought is to fit a gaussian density function to each spike and extract the x, y and z location of the peak. Can anybody give me a hint of how to do this? Thanks, Alan [[alternative HTML version deleted]]

...the LDA returns exit code 75, and the MTA will probably >>>> issue a bounce Email to the sender. >>> >>> which would be OK, if "never loose email contents" means "no message is >>> discarded silently". >> >> no, it is not OK to backscatter because the spamfilter fails >> >> realize that 99% auf junk is using forged senders >> >> recently i got each day some hundret such bounces from mailservers configured by fools reply to spam with forged senders and if i could i would have gone out for beat every responsible...

I noticed a mail stuck in my mail queue. dovecot-lda was returning error 64 Invalid parameter given. (EX_USAGE). Weird, weird, weird. After some sleuthing, I found the sender address was FirstLast at domain.tld, with a UTF8-encoded Unicode U+FEFF ZERO WIDTH NO-BREAK SPACE character (AKA byte order mark) between "First" and "Last" :) Since that is passed as the -f parameter to

Hi All, I'm just wanting to check that my understanding of the settings is correct as my web searches are finding a lot of dated information. If I want a Centos 6 sendmail system act as the secondary MX for domain bbbbb.co.uk do I just add a Connect:bbbbb.co.uk RELAY statement into /etc/mail/access and restart sendmail Obviously I have the DNS MX records for the domain are

Hello, i tried to implement a mixed structure of mbox for spams and spam backscatters and maildir for the rest at dovecot 1.0.13. I used the information at the dovecot wiki: http://wiki.dovecot.org/Namespaces (Multiple Mailbox Locations) But if i try this (complete config is attached with this part) namespace: type: private separator: / prefix: "#md/" location:...