SMTP "451 4.7.1 Try again later" SMTP responses

Support
21

set pre-result to ‘soft reject’ (no score): ‘Try again later’ from greylist(1)

what is the score of greylist

config show rspamd

try to disabled greylisting also

22 
rspamd=service
    BlockAttachmentClassList=Exec
    BlockAttachmentCustomList=iso,scr
    BlockAttachmentCustomStatus=enabled
    BlockAttachmentStatus=enabled
    OletoolsStatus=enabled
    Password=removed
    RecipientWhiteList=
    SenderBlackList=
    SenderWhiteList=
    SpamCheckStatus=disabled
    SpamGreyLevel=4
    SpamKillLevel=16
    SpamSubjectPrefixStatus=disabled
    SpamSubjectPrefixString=***SPAM***
    SpamTag2Level=7
    VirusAction=reject
    VirusCheckStatus=disabled
    VirusScanOnlyAttachment=false
    VirusScanSize=20000000
    isLoading=false
    status=enabled
23

I have the Antispam set to disabled and the problem is still happening.

24

image
image895×562 23.1 KB

25

Thanks @mark_nl @stephdl. I’ve disabled greylisting and will see what happens overnight.

26

like you see rspamd is still up

this is my settings

[root@prometheus ~]# config show rspamd | grep 'Spam'
    SpamCheckStatus=enabled
    SpamDsnLevel=20
    SpamGreyLevel=
    SpamKillLevel=19.9
    SpamNotification=disabled
    SpamNotificationStatus=enabled
    SpamSubjectPrefixStatus=enabled
    SpamSubjectPrefixString=***SPAM***
    SpamTag2Level=8
    SpamTagLevel=2
27

by curiosity what is the output of

rspamadm configdump | grep -A 5 'greylist'

greylist should be enabled = false;

28 
greylist_invalid = false;
    expire_novalid = 7200;
    symbol_no_mx = "MX_MISSING";
    enabled = true;
    key_prefix = "rmx";
    expire = 86400;
--
    greylist = null;
}
elastic {
    limit = 10;
    import_kibana = false;
    debug = false;
--
greylist {
    ipv6_mask = 64;
    whitelist_domains_url [
        "/etc/rspamd/local.d/greylist-whitelist-domains.inc",
        "/etc/rspamd/local.d/maps.d/greylist-whitelist-domains.inc",
    ]
    expire = 86400;
    key_prefix = "rg";
    enabled = false;
    ipv4_mask = 19;
29

Here (with setting shown in screen shot above):

# rspamadm configdump | grep -A 5 'greylist'
    greylist_invalid = false;
    expire_novalid = 7200;
    symbol_no_mx = "MX_MISSING";
    enabled = true;
    key_prefix = "rmx";
    expire = 86400;
--
    greylist = null;
}
elastic {
    limit = 10;
    import_kibana = false;
    debug = false;
--
greylist {
    ipv6_mask = 64;
    whitelist_domains_url [
        "/etc/rspamd/local.d/greylist-whitelist-domains.inc",
        "/etc/rspamd/local.d/maps.d/greylist-whitelist-domains.inc",
    ]
    expire = 86400;
    key_prefix = "rg";
    enabled = false;
    ipv4_mask = 19;

shows : enabled = false;

30

well for me the disabled state of rspamd is like it has not been saved in the UI, in a workable rspamd, each plugin gets :expressionless:

 greylist {
    enabled = false;
}
mime_types {
    enabled = false;
}
31

AFAIK greylisting (451 4.7.1 Try again later”) is totally following the RFC related to SMTP and therefore shouldn’t pose any problem. I’d look somewhere else.

The server being not accessible is a better track I guess.

1 Like
32

It is true, if postfix cannot use the rspamd linux socket you have also a try again later, but the evidence is in maillog, you can state on it

33

@pagaille
@stephdl

In the end it was in fact two problems. The 4.7.1 was due to greylisting behaviour which you helped me with, thank you. This explains Scenario 2 in my first post.

But also, one of my inbound MX IP was getting banned by fail2ban I found so I had to whitelist that IP which explained Scenario 1. Other MX IP we not banned, I am not sure why this was happening but everything is back to normal now.

2 Likes
34

Fail2ban helps to ban bad login to postfix, ddos and also a specific jail to prevent to use your smtp too many times to send email iirc about 100 email/minutes per IP

35

Maybe the greylist rejections increased the number of retries from my MX provider and triggered the ban.

1 Like
36

only fail2ban log can bring some answers

37

I realize this is a very old post, but maybe this will help someone in the future. In my case it had nothing to do with the file or folder protections or ownership. My dkim value in DNS did not EXACTLY match the opendkim file!!
I regenerated it to be sure and put the correct value in DNS. Everything then worked great.
A more accurate error message could have saved me HOURS or work.

1 Like
38

Welcome to NethServer community.

Thanks for sharing your solution to help others.
I think the error is more general and can have multiple reasons but every solution can be helpful.

1 Like