Posts made by anthonyh

I love friendly and healthy discussion about a certain topic. If I'm not posting for help (as in, CRAP this is broken how do I fix it?!), I'm posting because I want the opinions and experience of the members of the board.

What drives me nuts is when people post statements similarly to "well if you're not doing X then you're an idiot." That is NOT HELPFUL.

Also what drives me nuts is when people don't take the time to read the entire OP before responding. On SW more often than not I've had a lot of quick spastic replies to posts I've made and it's obvious they either didn't read the OP completely or did not understand what I was asking. They often feel like "points" posts. I then have to regurgitate my OP multiple times and it's frustrating.

I participate in communities like SW and ML because I am the first to admit that I do NOT know nor have experienced everything from every angle. Having input from the diversity of these communities helps me grow as an IT professional. And, who knows, maybe my post will help someone out in the future.

From the link I posted (https://www.ietf.org/rfc/rfc2821.txt). Of course, it's all "should", so it's dependent on how the sending server is configured.

4.5.4.1 Sending Strategy

The general model for an SMTP client is one or more processes that
periodically attempt to transmit outgoing mail. In a typical system,
the program that composes a message has some method for requesting
immediate attention for a new piece of outgoing mail, while mail that
cannot be transmitted immediately MUST be queued and periodically
retried by the sender. A mail queue entry will include not only the
message itself but also the envelope information.

The sender MUST delay retrying a particular destination after one
attempt has failed. In general, the retry interval SHOULD be at
least 30 minutes; however, more sophisticated and variable strategies
will be beneficial when the SMTP client can determine the reason for
non-delivery.

Retries continue until the message is transmitted or the sender gives
up; the give-up time generally needs to be at least 4-5 days. The
parameters to the retry algorithm MUST be configurable.

A client SHOULD keep a list of hosts it cannot reach and
corresponding connection timeouts, rather than just retrying queued
mail items.

Experience suggests that failures are typically transient (the target
system or its connection has crashed), favoring a policy of two
connection attempts in the first hour the message is in the queue,
and then backing off to one every two or three hours.

The SMTP client can shorten the queuing delay in cooperation with the
SMTP server. For example, if mail is received from a particular
address, it is likely that mail queued for that host can now be sent.
Application of this principle may, in many cases, eliminate the
requirement for an explicit "send queues now" function such as ETRN
[9].

The strategy may be further modified as a result of multiple
addresses per host (see below) to optimize delivery time vs. resource
usage.

@BRRABill said in Backup MX or no?:

@anthonyh said in Backup MX or no?:

This article was written around a specific mail platform, and is roughly 4 years old, but I'm curious on y'all's opinion. It's an argument against a secondary/backup MX.

https://blog.zensoftware.co.uk/2012/07/02/why-we-tend-to-recommend-not-having-a-secondary-mx-these-days/

It brings up an interesting question that hopefully someone here can answer.

What does happen to a piece of e-mail that is sent when your server is down? Does it really go back to the sending server, and queue up to be retried?

I'm no expert, but my understanding is that SMTP was written with the idea that the Internet is not reliable. Therefore, RFC compliant SMTP servers should queue messages and periodically re-try sending for a period of time.

There is a bunch of info here (thanks, Google!): https://www.ietf.org/rfc/rfc2821.txt

This article was written around a specific mail platform, and is roughly 4 years old, but I'm curious on y'all's opinion. It's an argument against a secondary/backup MX.

https://blog.zensoftware.co.uk/2012/07/02/why-we-tend-to-recommend-not-having-a-secondary-mx-these-days/

@scottalanmiller said in Backup MX or no?:

Any reason you don't have an existing service for this? With in house email I would typically still have a service for this "out front". You could implement that now and problem solved.

Nobody has ever thought it was a need. It hasn't really been an issue.

@aaronstuder It's dumb, I know.

@aaronstuder said in Backup MX or no?:

@anthonyh I think your confused... The backup MX service is already hosted... They just forward emails along to your server, unless your server is down then they store them.

No, I'm not confused.

I understand that this only comes into play with our primary MX is down (or if a non-compliant SMTP server sends to our backup MX).

It's a matter of trust. Yes, they'll forward our mail to us when we're back up, but we have no control of what else they do with said data. It's a control issue.

@aaronstuder said in Backup MX or no?:

@anthonyh $30 a year seems like a no brainer to me. I can help you with DNS records if you need it.

DNS is a non-issue. I'd just need to host whatever does backup MX for us on-site or invest in a AWS or Azure VM of some sort that I can control. For this purpose though something on-site would be fine.

@aaronstuder said in Backup MX or no?:

Regardless of this project, if your going to host email on site, you should have a backup MX provider.

What do you do when the server fails, or you misconfigure something? Just lose mail? That seems like a bad plan.

Depending on how something is misconfigured, you can still lose mail. I haven't experienced it personally, but I've heard of scenarios where a mail server was "accepting" mail, but the mail was lost. shrug

We've had a couple of outages before and just dealt with it. One was a mail server outage (it ran out of disk space the first week I was here), the other was an ISP outage. It's never been a big deal really. We let our users know what to expect when events occur.

Just trying to reach a good KISS balance. If a backup MX makes sense (which it's sounding like it might), then I'll do it.

@Breffni-Potter said in Backup MX or no?:

It's very easy to do, the only question is, how much mail do you need to clean before you release it onto your server? i.e spam.

If you have 20 or so users, it might not be so bad to skim through and delete the obvious ones.

If you have 200 users, well that becomes a job.

We have 400 mail accounts. So this gives me pause. Though, in theory, wouldn't my mail server handle the incoming messages from the backup MX as it would anything else?

Also, I'd need to set this up in-house. I'd love to jump on a cloud based service for this, but we're not there yet.

I'm going to be doing some email maintenance this weekend (moving Zimbra from Ubuntu to CentOS). I have a plan laid out and things should go smoothly, but we will still be down for a while. My plan of attack is so:

• Block mail related ports on existing server so no new mail comes in.
• Perform incremental backup of all mailboxes
• Restore backup to new server (this will take a while)
• Re-IP new server to match old
• Test send/receipt of mail
• If all is good, $profit

I suspect between the incremental backup and subsequent restore to the new server will take 4 or so hours. Add in 2 hours buffer for accommodating "unknowns" that come up (there is always a mailbox or two that fail to restore for some reason).

Do you think it would be worth setting up a backup MX to receive mail while we are down? Or is relying on the sending mail servers to retry/bounce if TTL is reached good enough?

I suppose there is equal risk of losing mail due to error on my part in configuring a backup MX (I've never done it before) as there is with mail servers that don't properly handle undeliverable messages. Also, I'd need to deal with spam on the backup MX too.

Thoughts?

@scottalanmiller

Understood. I need to figure out a way to parse the file so that the process finds "user=" and pulls everything after it until it hits the following ";", then finds "ip=" and pulls everything after it until it hits the following ";"

@scottalanmiller said in File Parsing Magic:

Put the file that you want to process into file2parse and this will do the rest...

#!/bin/bash

while read line; do
  echo $(echo $line | cut -d'=' -f2 | cut -d';' -f1)";"$(echo $line | cut -d'=' -f4 | cut -d';' -f1)
done < file2parse

This works 75% of the time, but it looks like some log entries show when a user is syncing an item shared by another user, which does not result in the desired output.

mailbox.log.2016-04-19:2016-04-19 01:27:53,338 INFO [qtp509886383-480009:https://10.39.6.4:443/service/soap/SyncRequest] [[email protected];[email protected];mid=14;ip=10.39.253.62;ua=ZCO/8.6.0.1320 (6.1.7601 SP1 en-US) P9b4 T1404;] soap - SyncRequest elapsed=4

What happens here is you get the following:

[email protected];14

Desired output is:

[email protected];10.39.253.62

@scottalanmiller said in File Parsing Magic:

Put the file that you want to process into file2parse and this will do the rest...

#!/bin/bash

while read line; do
  echo $(echo $line | cut -d'=' -f2 | cut -d';' -f1)";"$(echo $line | cut -d'=' -f4 | cut -d';' -f1)
done < file2parse

OMG SAM you are the best!

Sorry for not being clear. This is all under Linux VMs on-prem in my own environment (XenServer).

I have a log that I need to pull some data from. The entries look like this:

2016-04-21 07:11:34,512 INFO [qtp509886383-547489:https://10.39.6.4:443/service/soap/SyncRequest] [[email protected];mid=66;ip=10.39.248.191;ua=ZCO/8.6.0.1320 (6.2.9200 en-US) P1248 T25c0;] soap - SyncRequest elapsed=3

What I need to do is pull the text between name= and ip= and ; so that I have the following:

[email protected];10.39.248.191

These log entries are variable lengths (various URLs), but the desire is to import the user and IP into a MySQL DB so I can pull distinct results.

Once I can get it into a delimited format I can take it from there.

Oh ML magicians, what do you suggest?

@DustinB3403 You must've caught this when I accidentally submitted before I was finished. So I "removed" the post, finished composing, then restored it. Sorry!

I have a couple of Windows VMs that have large virtual disks that I need to move to another SR. My experience with moving virtual disks attached to Windows guests using XenCenter has been less than ideal. The process seems to have issues more often than not. Oddly enough I have never had an issue with Linux guests.

These virtual disks are pretty hefty. 300 GB, 500 GB, and 1.5 TB respectively. The 1.5 TB virtual disk is a file server, so worst case is I can create a new disk on the destination SR, move the files and re-do the shares, then delete the old virtual disk. However, the 300 GB and 500 GB disks are our test/staging MS-SQL server, so not as easy to re-create.

Just this morning I took a chance and moved a 75 GB virtual disk (the boot disk for our test/staging MS-SQL server) and it sorta-failed. The disk was cloned, the new disk was attached to the guest, but the process halted with the following error:

"Failed","Migrating 1 virtual disks to 3PAR_Vol3_r6
Internal error: Xenops_interface.Internal_error("Domain.Xenguest_failure("Error while waiting for suspend notification: xenguest: xc_domain_save: [1] Save failed (22 = Invalid argument)")")
Time: 00:17:35","Pool 01","Apr 19, 2016 8:50 AM"

Luckily it was a matter of simply powering the guest on and deleting the original virtual disk, but the issues I've had give me pause with these larger disks.

Any suggestions on how to get these guys moved?

I found a slightly easier solution to this. For each pool member:

• Enter Maintenance Mode
• Disable multipathing
• Enable multipathing
• Exit Maintenance Mode

BOOM. Path counts are reset.

@travisdh1 said:

@anthonyh said:

@travisdh1 said:

@anthonyh said:

Hey All,

I have a pool of XenServer 6.5 hosts that share a FC SAN (an inherited configuration that will change when we upgrade, and for those of you who've read past posts of mine YES the hosts in question are the blades...please hold the lecture I know this is all bad ).

While I don't know how to fix you're issue, I have to give you a golf clap for that much

Ha, thanks.

I suspect detatching and re-attaching the SRs one by one will fix the issue, but that's not something I've ever done in test, much less production...so I don't know what the implications are of doing that. If an SR that a VM's virtual disks resides on is detatched, what happens to said VM?

I'd suspect that you'd have to move any VM attached to the SR you are working with to a different SR, or shut down the VM.

Hmm. While it'd be a PITA, I suppose I could shuffle the SRs one by one. Create a new SR of equal size, migrate the disks, delete old SR, rinse and repeat. It would at least be a solution, and possibly a solution with minimal downtime...

@travisdh1 said:

@anthonyh said:

Hey All,

I have a pool of XenServer 6.5 hosts that share a FC SAN (an inherited configuration that will change when we upgrade, and for those of you who've read past posts of mine YES the hosts in question are the blades...please hold the lecture I know this is all bad ).

While I don't know how to fix you're issue, I have to give you a golf clap for that much

Ha, thanks.

I suspect detatching and re-attaching the SRs one by one will fix the issue, but that's not something I've ever done in test, much less production...so I don't know what the implications are of doing that. If an SR that a VM's virtual disks resides on is detatched, what happens to said VM?