What is the throttling rate that GTalk applies to XMPP messages? - xmpp

Even after throttling down to one message per second, after about 20 messages GTalk starts bouncing XMPP messages with ...
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What is the maximum send rate for XMPP messages through Google Talk?

i too experienced throttling from talk.google.com, but i can't find any documentation on it. The client from within gmail doesn't seem to have that same restriction. I was able to do paste and enter quickly to simulate it.

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Determining maximum accepable email lag

This question is not 100% technical. I've looked online and I couldn't find this being discussed.
We have a forgot username feature in our website which mails the username to the user's email address, using our own mail server.
We also put a message in the web-page asking the user to wait for 20 minutes for the mail to arrive since there can be occasional delays.
Our business tester raised an interesting point saying that 20 minutes seems an unacceptable time to ask the user to wait for. He said our technology should send emails immediately and the maximum lag should be 1 minute at worst.
Firstly, emails are usually received immediately by the recipient so there isn't a problem there.
But in our experience in using other websites, sometimes emails do take a while to arrive. I also remember reading somewhere that emails (at a network level) use a lower quality of service QoS unlike voip services. I can't seem to find it now.
Users can also experience delays in receiving emails because of issues in their own mail server.
Now, all we can do is send the mail using our mail server and ensure that the load and resources on the server is well managed.
1) Is there anything else we can do to ensure that our mails are sent quickly at all times.
2) What is the acceptable time, we can ask the user to wait until he logs a call with help-desk? I believe that there can be lags at a network/protocol level and the user's mail server which we can't do anything about.
Thanks.
All you can do is to inform user that your server "handed over" responsibility for email delivery to named SMTP server "beyond your control/responsibility". You may expect it would take a few (<5s) in most cases (>50%).
Your smtp-client may try initial delivery attempt.
On delivery success => inform the user that email delivery/delay is now beyond your control
On (initial) delivery failure => pass message to your SMTP server (with initial delivery attempt skipped).

Strophe XMPP receiving only stanzas with full JID

I'm creating a web XMPP client to connect to an XMPP ejabberd server and I have the following problem:
My client can send messages just alright.
The problem is when I try to receive messages. I only receive stanzas directed to my full JID, that is including the resource I am using, so I don't receive stanzas directed to my user#domain but I do receive stanzas sent to my user#domain/resource.
This is not an ideal situation since the other clients I need to communicate with work with bare JIDs.
I have little experience with Strophe so maybe someone with more experience can illustrate what I'm doing wrong. Thanks in advance!
Have you checked if your xmpp server offers a setting to route messages to all resources?
OpenFire offers a property named route.all-resources which will forward messages to all resources for a person.
Also, you may want to adjust the priority of your resource, as only the resource with the highest priority will have the message sent to it (if the message does not specify a resource).
Here is an example of setting your resource priority to 10 with Strophe.js
connection.send($pres().c("priority").t("10"));
This article describes the intended behaviour, and also this answer from a related question may help you understand what's happening.

How does Google Talk replicate messages across devices?

I'm wondering how (official) GTalk clients manage to show all messages received - even if it was originally consumed by another client. For example: I'm logged into GTalk on gmail.com on my laptop and, at the same time, via the official GTalk app on my Android device. A friend sends me a message, which is displayed on both the gmail.com client and the Android client. (I think it's originally only forwarded to one of either clients, but the second client fetches the message later on)
I recently found out that there's a very similar XMPP feature, called Carbons. However, after a quick service discovery request Google's servers didn't advertise this feature. XEP-0313 and XEP-0136 look good too, but the servers don't advertise them either.
Possibly related question: Deliver Google Talk message to all logged in clients using XMPPPY
When you initiate a new chat then you should send the first message to the users bare Jid. This is what most clients are doing. When the GTalk server retrieves a chat message to a bare Jid it routes the message to all available resources. For all following messages in this conversation the clients normally pick up the Resource and send them to full Jids. The messages should not be replicated then.
Many other servers don't route message to bare Jids to all resources, but to the most available resource which is the client with the highest priority.
Here is a quote form the RFC:
If there is more than one resource with a non-negative presence priority then the
server MUST either
(a) deliver the message to the "most available" resource or
resources (according to the server's implementation-specific algorithm, e.g., treating
the resource or resources with the highest presence priority as "most available") or
(b) deliver the message to all of the non-negative resources.
XEP-0280 defines this. As I understand, it defines the mechanism to notify all the resources from same user when one of them sends a message to anyone. I mean, Alice/pda sends a message to Bob, so Alice/mobile and Alice/PC will receive a copy of the message sent be Alice/pda.
Hope it helps. I am currently looking for a server that implements this, and also for a client library. If not, I will implement it by myself in both jabberd2 and gloox xmpp library.
Cheers,

What are the best practices for applications that need to send automatic emails (like password recovery service) and avoid e-mail blacklists?

I work at a university, on a project for a web driven academic management system and I'm currently facing the following problem:
Sometimes the application needs to send e-mails, most of then are sent on demand (users ask for a password recovery link, for example). Many emails for this kind of service are sent daily, and if on a peak of access they are sent massively. This has caused our email server to be included in blacklists of common email providers (like yahoo and hotmail), resulting in failures on email delivery.
What are the common causes for this kind of problem? Is it possible to avoid these blacklists? Or at least is there any good practices to follow so I can "flag" these useful emails as non-spam or safe email?
thanks for reading.
first of all, check if those messages are really sent to email addresses in your account database. maybe there is a security hole in your application that allows sending messages to arbitrary recipients. an indicator of that would be if your domain or ip is blacklisted not only at specific providers like yahoo or hotmail, but also on public blacklists like spamhaus.
("most of then are sent on demand".. makes me think.. what about the others? could they be interpreted as spam by many recipients?)
then you need to find out if your server is blocked due to
the amount of messages sent or due to the content looking "spammy".
Check your logs from the time before the blacklisting happens. Do you see many deferred messages (4xx error code), do they contain error messages that indicate too many messages from your IP?
if so, configure your MTA to throttle message delivery to those providers.
also check your mailserver setup:
correct fully qualified HELO?
matching reverse dns?
If you have DKIM , SPF and the like... are the settings correct?
finally, examine the generated messages. Do they have all required headers? Run them through spamassassin and check the result. adapt the formatting of your messages accordingly.

Send XMPP message without starting a chat

I am basically writing a XMPP client to automatically reply to "specific" chat messages.
My setup is like this:
I have pidgin running on my machine configured to run with an account x#xyz.com.
I have my own jabber client configured to run with the same account x#xyz.com.
There could be other XMPP clients .
Here is my requirement:
I am trying to automate certain kind of messages that I receive on gtalk. So whenever I receive a specific message eg: "How are you" , my own XMPP client should reply automatically with say "fine". How are you". All messages sent (before and after my client replies) to x#xyz.com but should be received by all clients (my own client does not have a UI and can only respond to specific messages.).
Now I have already coded my client to reply automatically. This works fine. But the problem I am facing is that as soon as I reply (I use the smack library), all subsequent messages that are sent to x#xyz.com are received only by my XMPP client. This is obviously a problem as my own client is quite dump and does not have a UI, so I don't get to see the rest of the messages sent to me, thereby making me "lose" messages.
I have observed the same behavior with other XMPP clients as well. Now the question is, is this is a requirement of XMPP (I am sorry but I haven't read XMPP protocol too well). Is it possible to code an XMPP client to send a reply to a user and still be able to receive all subsequent messages in all clients currently listening for messages? Making my client a full fledged XMPP client is a solution, but I don't want to go that route.
I hope my question is clear.
You may have to set a negative presence priority for your bot..
First thing to know is that in XMPP protocol every client is supposed to have a full JID. This is a bare JID - in your case x#xyz.com with a resource in the end e.g. x#xyz.com/pidgin or x#xyz.com/home (where /pidgin and /home are the resource). This is a part of how routing messages to different clients is supposed to be achieved.
Then there are the presence stanzas. When going online a client usually sends a presence stanza to the server. This informs about e.g. if the client is available for chat or away for lunch. Along with this information can be sent a priority. When there are more than one clients connected the one with the highest priority will receive the messages sent to the bare JID (e.g. ClientA(prio=50) and ClientB(prio=60) -> ClientB receives the messages sent to x#xyz.com). But there are also negative priorities. A priority less than 0 states that this client should never be sent any messages. Such a stanza might look like this
<presence from="x#xyz.com/bot">
<priority>-1</priority>
</presence>
This may fit your case. Please keep in mind it also depends on the XMPP server where your account is located, which may or may have not fully implemented this part of the protocol.
So to summarize: I recommend you to look through the Smack API how to set a presence and set the priority to <0 for your bot client right after it connected.