Date: Sat, 10 Sep 2016 00:28:40 +0200 From: "Julian H. Stacey" <jhs@berklix.com> To: freebsd-net@freebsd.org Cc: "Julian H. Stacey" <jhs@berklix.com> Subject: possible disruption of dovecot traffic on 1 of 2 freebsd hosts Message-ID: <201609092228.u89MSeUn099239@fire.js.berklix.net>
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Hi freebsd-net@freebsd.org I'm seeing strange net behaviour with POP3 on 1 of 2 servers, I would appreciate advice please, perhaps name of net tools to test with ? I have 1 local client POP3 fed from 2 remote servers: land.berklix.org a jail under another FreeBSD. FreeBSD land.berklix.org 10.3-RELEASE-p4 FreeBSD 10.3-RELEASE-p4 #0: Sat May 28 12:23:44 UTC 2016 root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64 slim.berklix.org under vmware, dont know whats outside FreeBSD slim.berklix.org 10.3-STABLE FreeBSD 10.3-STABLE #0: Tue Aug 16 18:09:22 CEST 2016 jhs@slim.berklix.org:/usr/obj/usr/src/sys/GENERIC amd64 slim also has /etc/rc.conf vmware_guest_vmblock_enable="YES" vmware_guest_vmhgfs_enable="YES" vmware_guest_vmmemctl_enable="YES" # ports/emulators/open-vm-tools-nox11 vmware_guest_vmxnet_enable="YES" # ports/emulators/open-vm-tools-nox11 vmware_guestd_enable="YES" # ports/emulators/open-vm-tools-nox11 Both land & slim run POP3 servers: /usr/ports/mail/dovecot # pkg info | grep dovecot # dovecot-1.2.17_6 All src/ & ports/ self compiled (though not kernels of prison & vmware). host land is reliable I can always succeed with fetchmail land.berklix.org host slim I can fetchmail for a while, then it locks up & periodically & I must manualy mv & sftp /var/mail/jhs The receiving local client shows this: fetchmail -v -v slim.berklix.org ........ fetchmail: SMTP> MAIL FROM:<MAILER-DAEMON@slim.berklix.org> SIZE=14380 fetchmail: SMTP< 250 2.1.0 <MAILER-DAEMON@slim.berklix.org>... Sender ok fetchmail: SMTP> RCPT TO:<jhs@localhost> fetchmail: SMTP< 250 2.1.5 <jhs@localhost>... Recipient ok fetchmail: SMTP> DATA fetchmail: SMTP< 354 Enter mail, end with "." on a line by itself #**************************.**********************.************************.**************.*************.**************.**************.**************.**************.**************.*************.**************.**********fetchmail: socket error while fetching from jhs@slim.berklix.org fetchmail: 6.3.8 querying slim.berklix.org (protocol POP3) at Fri Sep 9 22:49:31 2016: poll completed fetchmail: discarding new UID list fetchmail: Query status=2 (SOCKET) fetchmail: Deleting fetchids file. fetchmail: normal termination, status 2 fetchmail: Deleting fetchids file. /var/log/maillog: Land: dovecot: POP3(jhs): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0 Slim: dovecot: POP3(jhs): Connection closed: Connection reset by peer top=1/14385, retr=0/0, del=0/9, size=112436 Nothing suspicious in /var/log/messages on slim Strangely, I can sftp this /var/mail/jhs data to host=land, then I can fetchmail it from host=land no problem. Makes me suspect a packet problem ? I have kept 2 samples of that data, so can repeat this. I've noticed some stickiness on ssh session to host=slim in last weeks (& slim is a newish (some weeks) re-installation of FreeBSD on a newish vmwaee host (previous hardware problem) so something might have changed.) I'm wondering what tools to use to analyse & compare connections between home to both servers ? Reccomendations from /usr/ports/net/ I guess ? I'm rusty, but I guess it can't be eg something like long ago DSL MTU length issue, cos the same DSL link when up, works fine from host=land, just not from host=slim Can't be something weird in my dovecot POP3 server config, because both have identical symbolic links /usr/local/etc/dovecot.conf -> ../../../site/usr/local/etc/dovecot.conf & /site is frequently updated on both to keep identical my .fetchmailrc entries to fetch from both server are symmetric too. It's not some differential packet filtering in kernel issue, as with ipfw show land (jailed, work ok) ipfw: socket: Operation not permitted slim (vmware, locks up occasionaly, Ive not compiled ipfw in my kernel) ipfw: getsockopt(IP_FW_GET): Protocol not available I do have an ipfw rule set on my home gate, but neither those nor the 2 IPs of remote server have changed in a long time, I wrote them symmetricly way back, used to work on both, can't be that. Top shows both hosts 96 to 99% idle most of the time. Any suggestion of net / packet performance tools I might run please ? PS I am subscribed to net@freebsd.org, but a CC to me also nice, Thanks ! Cheers, Julian -- Julian Stacey, BSD Linux Unix Sys Eng Consultant Munich Reply below, Prefix '> '. Plain text, No .doc, base64, HTML, quoted-printable. http://berklix.eu/brexit/#stolen_votes
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