You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@tomcat.apache.org by vi...@thepenguin.org on 2013/01/09 13:31:09 UTC
Communication flow with different connectors
Hello:
I am seeking to understand the differences between using mod_jk and mod_ajp and mod_proxy_ajp. Ideally I would love to see a diagram of communication between apache and tomcat, but I haven't found anything like that. I want to confirm my understanding of the data flow. Can someone explain the three functionally or point me to a site that does?
Thanks,
CaptainVic
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by "Howard W. Smith, Jr." <sm...@gmail.com>.
On Wed, Jan 9, 2013 at 2:19 PM, Mark Thomas <ma...@apache.org> wrote:
> It varies. There is normally a link advertised on the conference web
> site. For the most recent ApacheCon (EU 2012) you want:
> http://archive.apachecon.com/eu2012/presentations/
>
> Others should be available id you start here:
> http://archive.apachecon.com/c/
>
> Any presentation I give is available from:
> http://people.apache.org/~markt/presentations/
>
Wow, really really nice. Will have to take a look. Thanks Mark!
Re: Communication flow with different connectors
Posted by Mark Thomas <ma...@apache.org>.
On 09/01/2013 18:37, Howard W. Smith, Jr. wrote:
> Chris,
>
> On Wed, Jan 9, 2013 at 10:33 AM, Christopher Schultz <
> chris@christopherschultz.net> wrote:
>
>> Mark Thomas is giving a talk at ApacheCon (Portland, OR, USA, 26 Feb
>> 2013) about Clustering Tomcat[1]. If you can make it, please join him.
>> If not, I'm sure his slides will be available afterward.
>>
>
> Thanks for the response. Where are the slides usually stored/archived and
> where will the slides of that talk possibly be stored/archived?
It varies. There is normally a link advertised on the conference web
site. For the most recent ApacheCon (EU 2012) you want:
http://archive.apachecon.com/eu2012/presentations/
Others should be available id you start here:http://archive.apachecon.com/c/
Any presentation I give is available from:
http://people.apache.org/~markt/presentations/
Mark
>
> I have made some nice strides since I started using Apache TomEE/Tomcat7.
> Looking forward to success in clustering Tomcat. For now, I will tune-in on
> this topic and read tomcat/etc documentation, and ask any questions when I
> have bandwidth to complete this task.
>
> Howard
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by "Howard W. Smith, Jr." <sm...@gmail.com>.
Chris,
On Wed, Jan 9, 2013 at 10:33 AM, Christopher Schultz <
chris@christopherschultz.net> wrote:
> Mark Thomas is giving a talk at ApacheCon (Portland, OR, USA, 26 Feb
> 2013) about Clustering Tomcat[1]. If you can make it, please join him.
> If not, I'm sure his slides will be available afterward.
>
Thanks for the response. Where are the slides usually stored/archived and
where will the slides of that talk possibly be stored/archived?
I have made some nice strides since I started using Apache TomEE/Tomcat7.
Looking forward to success in clustering Tomcat. For now, I will tune-in on
this topic and read tomcat/etc documentation, and ask any questions when I
have bandwidth to complete this task.
Howard
Re: Communication flow with different connectors
Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Howard,
On 1/9/13 9:40 AM, Howard W. Smith, Jr. wrote:
> On Wed, Jan 9, 2013 at 8:28 AM, Daniel Mikusa <dm...@vmware.com>
> wrote:
>
>> This is a good article that explains the different ways to proxy
>> to an Apache HTTPD server. It's a little old, but still good.
>>
>>
>> http://www.tomcatexpert.com/blog/2010/06/16/deciding-between-modjk-modproxyhttp-and-modproxyajp
>>
>
>>
> Interesting question and response, so far. Thank you both. I am
> tuning in on conversations related to httpd, tomcat, and SSL,
> because I already have a JSF web app deployed to tomcat7.0.34
> (TomEE 1.5.2-SNAPSHOT), and that is running well, but I want to run
> 2 instances of the web app against one database (with javaee6 L2
> cache) and SSL (https port to the outside world, only, but of
> course, not needed for those accessing the web app, behind the
> firewall, or accessing web app via the intranet).
Mark Thomas is giving a talk at ApacheCon (Portland, OR, USA, 26 Feb
2013) about Clustering Tomcat[1]. If you can make it, please join him.
If not, I'm sure his slides will be available afterward.
- -chris
[1] http://na.apachecon.com/schedule/presentation/122/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.17 (Darwin)
Comment: GPGTools - http://gpgtools.org
Comment: Using GnuPG with undefined - http://www.enigmail.net/
iEYEAREIAAYFAlDtjdYACgkQ9CaO5/Lv0PD5YACglVDBoSdWgx3EWE6/gKs4uyen
My8AoLqp+ZZ9s8XU361OiJyePv13e1gy
=PM4E
-----END PGP SIGNATURE-----
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by "Howard W. Smith, Jr." <sm...@gmail.com>.
On Wed, Jan 9, 2013 at 8:28 AM, Daniel Mikusa <dm...@vmware.com> wrote:
> This is a good article that explains the different ways to proxy to an
> Apache HTTPD server. It's a little old, but still good.
>
>
> http://www.tomcatexpert.com/blog/2010/06/16/deciding-between-modjk-modproxyhttp-and-modproxyajp
>
Interesting question and response, so far. Thank you both. I am tuning in
on conversations related to httpd, tomcat, and SSL, because I already have
a JSF web app deployed to tomcat7.0.34 (TomEE 1.5.2-SNAPSHOT), and that is
running well, but I want to run 2 instances of the web app against one
database (with javaee6 L2 cache) and SSL (https port to the outside world,
only, but of course, not needed for those accessing the web app, behind the
firewall, or accessing web app via the intranet).
Re: Communication flow with different connectors
Posted by vi...@thepenguin.org.
About the mail client, I am just unable to add a > or anything to the line automatically, so it gets confusing quickly if I post as I normally would. Now back to the issue:
My confusion was that I was unsure how have a mount allowed it to communicate. I hadn't really considered that the mount was associated with a worker and that the communication was handled that way. I understand a socket based communication like in mod_ajp, but I was missing how the mount was used. That is where I was coming from.
Thanks guys. I appreciate your responses.
CaptainVic
-----Original Message-----
From: "Christopher Schultz" <ch...@christopherschultz.net>
Sent: Wednesday, January 9, 2013 10:30am
To: "Tomcat Users List" <us...@tomcat.apache.org>
Subject: Re: Communication flow with different connectors
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Vicky,
On 1/9/13 9:06 AM, vicki@thepenguin.org wrote:
> I appreciate your reply and apologize for the top post (am using a
> stupid mail client from work).
You can't just press the /down/ arrow key a few times? *shrug*
> Your answer gets me part way there, but what is the most confusing
> to me is the use of JkMount. How does that fit into the picture
> from a communication perspective.
It's all configuration, not communication. Once configured, mod_jk and
mod_proxy_ajp work in exactly the same way (at least, the wire
protocol is the same -- the modules are obviously working somewhat
differently, internally).
Basically:
worker.foo.host=tomcat
worker.foo.port=8009
+
JkMount /myapp/* foo
is the same thing as this:
ProxyPass /myapp/ ajp://tomcat:8009/myapp/
ProxyReversePass /myapp/ ajp://tomcat:8009/myapp/
mod_jk's older configuration uses a separate file to configure the
workers, then JkMount directives in httpd.conf in order to map URLs to
those workers. mod_proxy_ajp's configuration is done all in httpd.conf
and matches the configuration of all mod_proxy_* modules.
The configuration becomes more complex for both modules when using
load-balancing. mod_jk uses a single worker of type "lb" with other
workers actually connecting to Tomcat instances, then you use JkMount
as usual with the "lb" worker, so httpd.conf need not change at all to
introduce load-balancing. mod_proxy uses a <Proxy> directive to define
a balancer with various BalancerMember directives and then uses a
ProxyPass directive to map a URL space to that balancer, so httpd.conf
becomes more complicated when load-balancing is introduced.
Note that you can configure mod_jk entirely within httpd.conf if you
want, using JkWorkerProperty. I don't believe you can configure mod_jk
using such compact syntax as mod_proxy supports, yet mod_jk does
support "template" workers which can significantly simplify your
deployment if you have many workers to track.
Hope that helps,
- -chris
-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.17 (Darwin)
Comment: GPGTools - http://gpgtools.org
Comment: Using GnuPG with undefined - http://www.enigmail.net/
iEYEAREIAAYFAlDtjQMACgkQ9CaO5/Lv0PC8xACfaXUc/Xl7sGU+Rh/eURxxChtd
lR4AnjejrpdNTeExDevJ3eAkuTUN0m7g
=nFLK
-----END PGP SIGNATURE-----
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Vicky,
On 1/9/13 9:06 AM, vicki@thepenguin.org wrote:
> I appreciate your reply and apologize for the top post (am using a
> stupid mail client from work).
You can't just press the /down/ arrow key a few times? *shrug*
> Your answer gets me part way there, but what is the most confusing
> to me is the use of JkMount. How does that fit into the picture
> from a communication perspective.
It's all configuration, not communication. Once configured, mod_jk and
mod_proxy_ajp work in exactly the same way (at least, the wire
protocol is the same -- the modules are obviously working somewhat
differently, internally).
Basically:
worker.foo.host=tomcat
worker.foo.port=8009
+
JkMount /myapp/* foo
is the same thing as this:
ProxyPass /myapp/ ajp://tomcat:8009/myapp/
ProxyReversePass /myapp/ ajp://tomcat:8009/myapp/
mod_jk's older configuration uses a separate file to configure the
workers, then JkMount directives in httpd.conf in order to map URLs to
those workers. mod_proxy_ajp's configuration is done all in httpd.conf
and matches the configuration of all mod_proxy_* modules.
The configuration becomes more complex for both modules when using
load-balancing. mod_jk uses a single worker of type "lb" with other
workers actually connecting to Tomcat instances, then you use JkMount
as usual with the "lb" worker, so httpd.conf need not change at all to
introduce load-balancing. mod_proxy uses a <Proxy> directive to define
a balancer with various BalancerMember directives and then uses a
ProxyPass directive to map a URL space to that balancer, so httpd.conf
becomes more complicated when load-balancing is introduced.
Note that you can configure mod_jk entirely within httpd.conf if you
want, using JkWorkerProperty. I don't believe you can configure mod_jk
using such compact syntax as mod_proxy supports, yet mod_jk does
support "template" workers which can significantly simplify your
deployment if you have many workers to track.
Hope that helps,
- -chris
-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.17 (Darwin)
Comment: GPGTools - http://gpgtools.org
Comment: Using GnuPG with undefined - http://www.enigmail.net/
iEYEAREIAAYFAlDtjQMACgkQ9CaO5/Lv0PC8xACfaXUc/Xl7sGU+Rh/eURxxChtd
lR4AnjejrpdNTeExDevJ3eAkuTUN0m7g
=nFLK
-----END PGP SIGNATURE-----
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by André Warnier <aw...@ice-sa.com>.
Hi.
Let me just add a bit to Daniel's outline below.
vicki@thepenguin.org wrote:
> Hi Daniel:
>
> I appreciate your reply and apologize for the top post (am using a stupid mail client from work). Your answer gets me part way there, but what is the most confusing to me is the use of JkMount. How does that fit into the picture from a communication perspective. I hope this question is clear, but since my Google searches are not turning up anything, I fear that it won't be.
>
> Thanks,
> CaptainVic
>
> -----Original Message-----
> From: "Daniel Mikusa" <dm...@vmware.com>
> Sent: Wednesday, January 9, 2013 8:28am
> To: "Tomcat Users List" <us...@tomcat.apache.org>
> Subject: Re: Communication flow with different connectors
>
> On Jan 9, 2013, at 7:31 AM, vicki@thepenguin.org wrote:
>
>> Hello:
>>
>> I am seeking to understand the differences between using mod_jk and mod_ajp and mod_proxy_ajp.
>
> This is a good article that explains the different ways to proxy to an Apache HTTPD server. It's a little old, but still good.
>
> http://www.tomcatexpert.com/blog/2010/06/16/deciding-between-modjk-modproxyhttp-and-modproxyajp
>
>
>> Ideally I would love to see a diagram of communication between apache and tomcat, but I haven't found anything like that. I want to confirm my understanding of the data flow.
>
> Not quite sure what you mean by this, gonna take a couple guesses...
>
> 1.) If you are looking for an explanation of how a request travels from a client to Tomcat, then this might help.
>
> When using mod_jk or mod_proxy_ajp, traffic flows from the client to Tocmat like this...
>
> client -> HTTP(s) -> Apache HTTPD -> AJP -> Tomcat
>
> then from Tomcat back to the client over the same path.
>
> If using mod_proxy_http, it is similar but looks like this.
>
> client -> HTTP(s) -> Apache HTTPD -> HTTP(s) -> Tomcat
>
> then from Tomcat back to the client over the same path.
>
To expand a bit the above :
If we limit ourselves to the AJP protocol,
- on the Tomcat side, there is only one AJP Connector, and the communication protocol is
always the same.
- on the httpd side, the options are :
a)
client -> HTTP(s) -> (Apache HTTPD + mod_proxy + mod_proxy_ajp) -> AJP -> Tomcat
or
b)
client -> HTTP(s) -> (Apache HTTPD + mod_jk) -> AJP -> Tomcat
Which one you choose is mainly a matter of needs, convenience and preferences, as
explained here : http://wiki.apache.org/tomcat/FAQ/Connectors
About "JkMount" etc :
In the Apache httpd configuration context, the "JkMount" syntax and usage is sometimes a
bit awkward, because it does not follow the general pattern of other httpd configuration
directives, and it is not very clear where in the Apache request processing cycle it
intervenes.
But instead of JkMount/JkUnMount, there exists another mod_jk configuration possibility,
which is explained at the bottom of this page :
http://tomcat.apache.org/connectors-doc/reference/apache.html
(see the section : Using SetHandler and Environment Variables)
I find that configuring mod_jk in this way makes it easier to understand the way in which
it works. And it also allows you to use mod_jk in conjunction with other standard Apache
httpd configuration options, such as Alias, RewriteRule etc.
(JkMount/JkUnMount are a bit more obscure in terms of how they interplay with other httpd
configuration snippets).
For Apache httpd, mod_jk is a "response handler", which generates the response to a HTTP
request. After Apache has analysed the incoming HTTP request and mapped it to the
appropriate <Location> section, it hands the request to the configured response handler
for that section, and expects in return a response document (or an error) to pass back to
the client browser.
In this case, that response handler is "jakarta-servlet" (an alias for mod_jk).
Apache httpd basically has no idea that when it asks mod_jk to generate the response to a
request, mod_jk in the background is communicating with one or more back-end Tomcat
servers which do the real work.
(And the details of how mod_jk is doing this, are in the separate mod_jk configuration
file "workers.properties").
Does this help ?
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by Daniel Mikusa <dm...@vmware.com>.
On Jan 9, 2013, at 9:06 AM, vicki@thepenguin.org wrote:
> Hi Daniel:
>
> I appreciate your reply and apologize for the top post (am using a stupid mail client from work). Your answer gets me part way there, but what is the most confusing to me is the use of JkMount. How does that fit into the picture from a communication perspective. I hope this question is clear, but since my Google searches are not turning up anything, I fear that it won't be.
Sorry, I'm not sure I follow you here. JkMount is used to map a path onto a particular worker. Let's say a request comes in for "/your-app" and you have "JkMount /your-app worker1" in your HTTPD configuration. That would instruct mod_jk to take the request and send it to worker1. If a request came in for "/some-other-app", then mod_jk would do nothing because it does not match with what is configured by JkMount.
If you have not done so already, I would suggest you go through the docs and setup a playground environment. I think this is a good place to start.
https://tomcat.apache.org/connectors-doc/generic_howto/quick.html
Hope that helps.
Dan
>
> Thanks,
> CaptainVic
>
> -----Original Message-----
> From: "Daniel Mikusa" <dm...@vmware.com>
> Sent: Wednesday, January 9, 2013 8:28am
> To: "Tomcat Users List" <us...@tomcat.apache.org>
> Subject: Re: Communication flow with different connectors
>
> On Jan 9, 2013, at 7:31 AM, vicki@thepenguin.org wrote:
>
>> Hello:
>>
>> I am seeking to understand the differences between using mod_jk and mod_ajp and mod_proxy_ajp.
>
> This is a good article that explains the different ways to proxy to an Apache HTTPD server. It's a little old, but still good.
>
> http://www.tomcatexpert.com/blog/2010/06/16/deciding-between-modjk-modproxyhttp-and-modproxyajp
>
>
>> Ideally I would love to see a diagram of communication between apache and tomcat, but I haven't found anything like that. I want to confirm my understanding of the data flow.
>
> Not quite sure what you mean by this, gonna take a couple guesses...
>
> 1.) If you are looking for an explanation of how a request travels from a client to Tomcat, then this might help.
>
> When using mod_jk or mod_proxy_ajp, traffic flows from the client to Tocmat like this...
>
> client -> HTTP(s) -> Apache HTTPD -> AJP -> Tomcat
>
> then from Tomcat back to the client over the same path.
>
> If using mod_proxy_http, it is similar but looks like this.
>
> client -> HTTP(s) -> Apache HTTPD -> HTTP(s) -> Tomcat
>
> then from Tomcat back to the client over the same path.
>
>
> 2.) If you are looking for more details on the AJP protocol and how data is sent between HTTPD & Tomcat, I would suggest starting here.
>
> https://tomcat.apache.org/connectors-doc/ajp/ajpv13a.html
>
> Then I would suggest that you run Wireshark and take a look at some actual traffic. It gives you a good visualization of the traffic.
>
>
> 3.) Something else? Please try to explain more.
>
>
>> Can someone explain the three functionally or point me to a site that does?
>
> See above.
>
> Dan
>
>>
>> Thanks,
>> CaptainVic
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by vi...@thepenguin.org.
Hi Daniel:
I appreciate your reply and apologize for the top post (am using a stupid mail client from work). Your answer gets me part way there, but what is the most confusing to me is the use of JkMount. How does that fit into the picture from a communication perspective. I hope this question is clear, but since my Google searches are not turning up anything, I fear that it won't be.
Thanks,
CaptainVic
-----Original Message-----
From: "Daniel Mikusa" <dm...@vmware.com>
Sent: Wednesday, January 9, 2013 8:28am
To: "Tomcat Users List" <us...@tomcat.apache.org>
Subject: Re: Communication flow with different connectors
On Jan 9, 2013, at 7:31 AM, vicki@thepenguin.org wrote:
> Hello:
>
> I am seeking to understand the differences between using mod_jk and mod_ajp and mod_proxy_ajp.
This is a good article that explains the different ways to proxy to an Apache HTTPD server. It's a little old, but still good.
http://www.tomcatexpert.com/blog/2010/06/16/deciding-between-modjk-modproxyhttp-and-modproxyajp
> Ideally I would love to see a diagram of communication between apache and tomcat, but I haven't found anything like that. I want to confirm my understanding of the data flow.
Not quite sure what you mean by this, gonna take a couple guesses...
1.) If you are looking for an explanation of how a request travels from a client to Tomcat, then this might help.
When using mod_jk or mod_proxy_ajp, traffic flows from the client to Tocmat like this...
client -> HTTP(s) -> Apache HTTPD -> AJP -> Tomcat
then from Tomcat back to the client over the same path.
If using mod_proxy_http, it is similar but looks like this.
client -> HTTP(s) -> Apache HTTPD -> HTTP(s) -> Tomcat
then from Tomcat back to the client over the same path.
2.) If you are looking for more details on the AJP protocol and how data is sent between HTTPD & Tomcat, I would suggest starting here.
https://tomcat.apache.org/connectors-doc/ajp/ajpv13a.html
Then I would suggest that you run Wireshark and take a look at some actual traffic. It gives you a good visualization of the traffic.
3.) Something else? Please try to explain more.
> Can someone explain the three functionally or point me to a site that does?
See above.
Dan
>
> Thanks,
> CaptainVic
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Communication flow with different connectors
Posted by Daniel Mikusa <dm...@vmware.com>.
On Jan 9, 2013, at 7:31 AM, vicki@thepenguin.org wrote:
> Hello:
>
> I am seeking to understand the differences between using mod_jk and mod_ajp and mod_proxy_ajp.
This is a good article that explains the different ways to proxy to an Apache HTTPD server. It's a little old, but still good.
http://www.tomcatexpert.com/blog/2010/06/16/deciding-between-modjk-modproxyhttp-and-modproxyajp
> Ideally I would love to see a diagram of communication between apache and tomcat, but I haven't found anything like that. I want to confirm my understanding of the data flow.
Not quite sure what you mean by this, gonna take a couple guesses...
1.) If you are looking for an explanation of how a request travels from a client to Tomcat, then this might help.
When using mod_jk or mod_proxy_ajp, traffic flows from the client to Tocmat like this...
client -> HTTP(s) -> Apache HTTPD -> AJP -> Tomcat
then from Tomcat back to the client over the same path.
If using mod_proxy_http, it is similar but looks like this.
client -> HTTP(s) -> Apache HTTPD -> HTTP(s) -> Tomcat
then from Tomcat back to the client over the same path.
2.) If you are looking for more details on the AJP protocol and how data is sent between HTTPD & Tomcat, I would suggest starting here.
https://tomcat.apache.org/connectors-doc/ajp/ajpv13a.html
Then I would suggest that you run Wireshark and take a look at some actual traffic. It gives you a good visualization of the traffic.
3.) Something else? Please try to explain more.
> Can someone explain the three functionally or point me to a site that does?
See above.
Dan
>
> Thanks,
> CaptainVic
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org