Re: [mailop] nolisting, was What's the point of secondary MX servers?
On 2020-12-19 16:43, John Levine via mailop wrote: In article <12329a9a-11a7-eda4-c88a-3dc352aea...@spamtrap.tnetconsulting.net> you write: On 12/18/20 12:29 PM, John Levine via mailop wrote: As I recall some sites were getting stuck on the nolist host for every message. Odd. Perhaps it has something to do with the type of nolisting. Did you have something listening on the IP address? Or was it reserved with nothing there? I think it was sending resets but as I said, it was a while ago. Back in the day, a number of servers were known to, uh, function suboptimally when presented with various things. I think the original unpatched qmail had one or two bits of weirdness about MX lookups and limited retries. You might remember the details. Exchange at one point was treating a "550" after a DATA as "hit me again ASAP". In one case 1.5 million retries in 8 hours. ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] nolisting, was What's the point of secondary MX servers?
In article <12329a9a-11a7-eda4-c88a-3dc352aea...@spamtrap.tnetconsulting.net> you write: > >On 12/18/20 12:29 PM, John Levine via mailop wrote: >> As I recall some sites were getting stuck on the nolist host for >> every message. > >Odd. > >Perhaps it has something to do with the type of nolisting. Did you have >something listening on the IP address? Or was it reserved with nothing >there? I think it was sending resets but as I said, it was a while ago. -- Regards, John Levine, jo...@taugh.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. https://jl.ly ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] nolisting, was What's the point of secondary MX servers?
On 12/18/20 12:29 PM, John Levine via mailop wrote: As I recall some sites were getting stuck on the nolist host for every message. Odd. Perhaps it has something to do with the type of nolisting. Did you have something listening on the IP address? Or was it reserved with nothing there? I've been using nolisting with something that sends a TCP reset for years and am not aware of any problems. -- Grant. . . . unix || die smime.p7s Description: S/MIME Cryptographic Signature ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] nolisting, was What's the point of secondary MX servers?
On 18 Dec 2020 19:29:21 -, John Levine via mailop wrote: >As I recall some sites were getting stuck on the nolist host for every >message. That would be the expected result. Few servers retain much in the way of state, beyond an optional "always use the first outgoing IP". The expectation is that the sender will use rotating DNS order for load balancing or failover. mdr -- The world was almost won by such an ape! The nations put him where his kind belong. But do not rejoice too soon at your escape. The womb he crawled from is still going strong. -- Bertold Brecht,"The Resistible Rise of Arturo UI" ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] nolisting, was What's the point of secondary MX servers?
In article <4178e3f3-de16-8d62-4810-8785dc095...@spamtrap.tnetconsulting.net>, Grant Taylor via mailop wrote: >-=-=-=-=-=- >-=-=-=-=-=- > >On 12/18/20 10:22 AM, John Levine via mailop wrote: >> I tried that for a while. I found that some senders took quite a >> while to give up on the nolist host and go to the backup so it caused >> noticable mail delays. > >How much delay were you seeing? It was a while ago, but I think hours. >How did that delay compare to grey listing? Particularly compared to >stateful grey listing and / or sending farms with rotating sending IPs. There's a lot of ways to do greylisting, most of which are overkill. Mine accepts a retry from any address in the same /24 as the original, and whitelists the IP indefinitely after a successful retry. So there is some delay the first time someone sends a message but not after that. As I recall some sites were getting stuck on the nolist host for every message. R's, John -- Regards, John Levine, jo...@taugh.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. https://jl.ly ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] nolisting, was What's the point of secondary MX servers?
On 12/18/20 10:22 AM, John Levine via mailop wrote: I tried that for a while. I found that some senders took quite a while to give up on the nolist host and go to the backup so it caused noticable mail delays. How much delay were you seeing? How did that delay compare to grey listing? Particularly compared to stateful grey listing and / or sending farms with rotating sending IPs. -- Grant. . . . unix || die smime.p7s Description: S/MIME Cryptographic Signature ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] nolisting, was What's the point of secondary MX servers?
In article <81acc49e-3f6c-0905-a952-f4786841a...@pscs.co.uk> you write: >There's also the opposite anti-spam trick that I've heard of: > >have two MX records. The higher priority MX just doesn't exist and the >real mail server is the lower priority one. Badly written spam software >will try the higher one and when that doesn't respond, it'll give up. >Well written mail senders try the higher one, then use the lower one >when the higher one doesn't respond. I tried that for a while. I found that some senders took quite a while to give up on the nolist host and go to the backup so it caused noticable mail delays. ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
