Message Queue Error Means in Exchange Server 2003

DSN messages pending submission This folder contains Delivery Status Notifications awaiting delivery. Its primarily used for NDR’s – Non Delivery Reports.

Failed message retry queue Contains outbound messages which couldn’t be delivered to their destination but will be given another attempt.

Local delivery Contains inbound messages for delivery to mailboxes on the Exchange server.

Messages awaiting directory lookup Contains inbound messages awaiting recipient lookup in Active Directory.

Messages pending submission Contains messages accepted by the SMTP virtual server, but haven’t yet been processed.

Messages queued for deferred delivery Contains messages queued for deferred delivery (later time).

Messages waiting to be routed Contains outbound SMTP/X400 messages still waiting to be routed to their destination server, when it has been determined the message will be sent.

Exchange Server 2003 Queue Problems and Troubleshooting

Queue: Messages pending submission

First Available: Exchange 2000 Service Pack 2

Description: This queue holds messages that have been acknowledged and accepted by the SMTP service.

Messages that are in this queue have not been processed.

Troubleshooting: If messages are constantly accumulating, you may have a performance problem. Occasional

peaks in CPU performance can cause messages to appear in this queue intermittently. Frequently, problems with

event sinks (for example, custom SMTP processing code for antivirus screening and for disclaimers) cause

messages to accumulate in this queue.

Queue: Messages awaiting directory lookup

First Available: Exchange 2000

Description: This queue contains messages to recipients who have not yet been resolved against the Microsoft

Active Directory directory service. Messages are also held in this queue while distribution lists are expanded.

Troubleshooting: Generally, messages accumulate in this queue because the advanced queuing engine cannot

categorize the message. The advanced queuing engine may not be able to access the global catalog servers or to

access the recipient information. Or, the global catalog servers are unreachable or are performing slowly. Increase

diagnostic logging for the MSExchangeDSAccess service and for the MSExchangeTransport service to collect

information about Categorizer components. To increase diagnostic logging for a component, review the steps that

are listed earlier in the "More Information" section of this article.

Queue: Messages waiting to be routed

First Available: Exchange 2000

Description: This queue holds messages until their next-destination server is determined. The messages are then

moved to their respective link queues.

Troubleshooting: Messages may accumulate in this queue if Exchange routing problems exist. For example,

message routing may be backed up. Disable any unnecessary connector restrictions because the restrictions can

cause a significant degradation in server performance. You may have to turn on the CheckConnectorRestrictions

registry key for some restrictions.

Also, increase diagnostic logging for the MSExchangeTransport service for the Routing category component to

gather additional information. To increase diagnostic logging for a component, review the steps that are listed

earlier in the "More Information" section of this article.

Queue: Local delivery (the domain name may appear)

First Available: Exchange 2000

Description: This queue contains messages that have been queued on the Exchange Server computer for local

delivery to an Exchange mailbox.

Troubleshooting: Messages may accumulate in this queue if the information store is not accepting messages for

local delivery. Slow or sporadic message delivery can indicate that a looping message or that a performance

problem exists. Increase diagnostic logging for the MSExchangeIS service and for the MSExchangeTransport service

for the SMTP Store Driver components.

Queue: Remote delivery queue (this queue contains the name of the connector or of the destination server with

the domain)

First Available: Exchange 2000

Description: This queue contains messages that are destined for a remote delivery. The name of the queue

matches the remote delivery destination.

Troubleshooting: If the queue is in a retry state, click the queue to review the Additional Queue Information. This

information is located at the bottom of the right pane. Use the NSlookup utility to review possible issues with

Domain Name System (DNS) resolution. For connection and protocol issues such as "host unreachable" errors, use

Telnet.exe to try to connect to the destination computer. To troubleshoot protocol errors, increase diagnostic

logging for the MSExchangeTransport service for the SMTP Protocol component, and review the logs for errors.

Alternatively, you can use the Network Monitor tool to obtain information about network connection errors. To

reproduce the problem, you may have to force the queue to try again

Queue: Messages with an unreachable destination

First Available: Exchange 2000

Description: Messages in this queue cannot reach their final destination server. For example, Exchange cannot

determine a route or a connector to the final destination, or all available routes or connectors are marked as

down.

Troubleshooting: Messages can accumulate in this queue if no route exists for message delivery. Also, if an

Exchange connector or a remote delivery queue is unavailable or if it is in a retry status for a while, and no

alternative available route exists to the connector or the remote destination, new messages may be moved to this

queue. The administrator can then address the problem or define an alternative route. Use the WinRoute tool to

help determine available routes and route status

To troubleshoot the queue that is causing this issue, restart the SMTP Virtual Server to reset the connector status

and to retry the messages that are queued. To restart the SMTP virtual server, follow these steps:

Queue: Messages queued for deferred delivery

First Available: Exchange Server 2003

Description: This queue contains messages that are queued for later delivery. It includes messages that were sent

by older versions of Microsoft Outlook when this option is set. Newer versions of Outlook queue these types of

messages in the information store. These messages remain in this queue until their scheduled delivery time.

Troubleshooting: The following conditions can also cause messages to accumulate in this queue:

· A message is sent to a user’s mailbox while the mailbox is being

moved.

· The user does not yet have a mailbox, and no master account

security ID (SID) exists for the user.

· An administrator configures SMTP in a way that causes a message to

loop. SMTP moves these messages to this queue. This permits the

administrator to correct the problem without causing messages to

immediately return with "maximum hop count exceeded" errors.

Moving messages to this queue also helps to prevent too many

performance hits to the server resources.

Queue: DSN messages pending submission

First Available: Exchange Server 2003

Description: This queue contains delivery status notifications (DSN) that are waiting to be rendered by Exchange.

Delivery status notifications are also known as non-delivery reports (NDR).

Troubleshooting: Messages can accumulate in this queue when any of the following conditions exist:

· The Information Store service is unavailable or is not running.

· A private information store is not mounted.

· Issues exist with the IMAIL Exchange store component. IMAIL is the

component that performs message conversion.

Review the Windows application event log for errors in the Microsoft Exchange Information Store service.

Queue: Failed message retry

First Available: Exchange Server 2003

Description: Messages that failed a queue submission are moved to this queue. Frequently, messages fail a queue

submission before any other processing has been done. By default, messages in this queue are reprocessed in 60

minutes. Corrupted messages or low system resources can cause messages to appear in this queue.

Troubleshooting: Review third-party programs that are installed or event sinks that can interfere with message

queuing or message fidelity. If the computer responds slowly, use Windows Task Manager to determine processes

that may use too many system resources. Restarting the Internet Information Server service may provide

temporary relief until you can determine the root cause of the problem. To restart the Internet Information Server

service, follow these steps:

Queue: SMTP Mailbox Store (X.400)

First Available: Exchange 2000

Description: This queue contains messages that are processed by the SMTP components. Messages that have been

received and processed by the message transfer agent (MTA) must also be processed by the SMTP components,

even if the message is destined for remote locations that are serviced by the MTA. To submit messages to SMTP,

the MTA puts the messages in the SMTP mailbox inside the information store.

Troubleshooting: Make sure that at least one mailbox store is mounted and that the Microsoft Exchange

Information Store service is started. To troubleshoot protocol errors, increase diagnostic logging for the

MSExchangeMTA component.

Basic Exchange 2003 Troubleshooting

My mantra is getting you started, reminding you of the best places to check. Your role is that of a detective looking for clues. What is the significance of a red dot here, an error message there. Once you have assembled the clues it's time to develop a theory as to the underlying cause of the problem. Finally, draw up a list of possible solutions.

1. Open the Event Viewer and check the Application Log. 2. Can you send yourself an email? If necessary, use OWA: http: //server/exchange. 3. Ensure that all the necessary services are started, remember to scroll down to 'M' for Microsoft Exchange,

now you can see services like MSExchangeIS. 4. What happens if you go to the command prompt and type:

telnet servername 25? Do you get a Hello response? 5. Are there any clues in the Exchange System Manager, Servers, Queues

Troubleshooting a Corrupted Mailstore

If Event viewer reports MSExchangeIS errors, then the following utilities will help to resolve the problem. In an ideal world, you need experience of Eseutil and Isinteg utilities BEFORE disaster strikes. So practice some of the safer commands, for example eseutil /d or isinteg -s servername -tests alltests.

Eseutil - Powerful tool for repairing Exchange store databases IsInteg - Fixing corrupt tables in the store.

General Troubleshooting

Classic places to collect clues. Find out why the email did not get through.

NDR - Non Deliverable Reports ExBPA - Best Practice Analyzer Message Tracking Center - Built-in utility found in Exchange System Manager Queues Troubleshooting - Examining each logical queue WinRoute - Check Routing Group Masters, Link State and connectors

Troubleshooting Connections - Exchange Logs

If the email is not getting through, examine Exchange's logs. The biggest problem is finding the best log for your particular situation.

Exchange Logs - Home SMTP Raw Commands - ehlo, mail from: rcpt to: SMTP Auth Login - base64 encryption of password

NDR - Non Deliverable Reports SMTP Logs - W3C Extended Log File Format Diagnostic Logs - Extra information about exchange services

Troubleshooting Performance

If you feel that your server ought to be running faster, then take the time to create a counter log. Start with the big 4 objects, memory, processor, disk and network, then progress to Exchange specific counters such as MSexchangeIS (Information Store).

Performance Monitoring Advice - How to find bottlenecks on your network Performance Monitoring Memory - Investigate paging bottlenecks on your server Performance Monitoring Disks - Search for database or transaction log bottlenecks Performance Monitoring Processor - Check for CPU bottlenecks

Troubleshooting Tools

What ever the problem, always begin by checking the event viewer. I will be amazed if there is not a clue as to what's wrong with your Exchange Server in either the Application or System logs.

Event ID - Track down problems in the Application Log Registry - Add ShowSecurityPage and see the permissions in Exchange System Manager ADSI Edit - Learn about Active Directory attributes, for example tombstoneLifeTime HTTPMon - Monitor OWA and IIS SP1 for Exchange Server 2003 Rapid Reboot Script - Speed up your Exchange restarts WinRoute - Check Routing Group Masters, Link State and SMTP connectors Telnet - email domain on port 25 ExBPA - Best Practice Analyzer Tips for Troubleshooting - Advice on how to solve problems

NOTE: When you look up Event IDs in TechNet use 'near' in the search. For example, Event NEAR 7001. What NEAR does is in this example is return all occurrences of Event within 8 words of 7001.

NDR List of Codes and their meanings

NDR

Code

Explanation of Non-Delivery Report error codes for Exchange Server

4.2.2The recipient has exceeded their mailbox limit. It could also be that the delivery

directory on the Virtual server has exceeded its limit. (Default 22 MB)

4.3.1Not enough disk space on the delivery server. Microsoft say this NDR maybe

reported as out-of-memory error.

4.3.2 Classic temporary problem, the Administrator has frozen the queue.

4.4.1Intermittent network connection. The server has not yet responded. Classic

temporary problem. If it persists, you will also a 5.4.x status code error.

4.4.2 The server started to deliver the message but then the connection was broken.

4.4.6 Too many hops. Most likely, the message is looping.

4.4.7 Problem with a timeout. Check receiving server connectors.

4.4.9

A DNS problem. Check your smart host setting on the SMTP connector. For

example, check correct SMTP format. Also, use square brackets in the IP address

[197.89.1.4] You can get this same NDR error if you have been deleting routing

groups.

4.6.5Multi-language situation. Your server does not have the correct language code page

installed.

5.0.0

SMTP 500 reply code means an unrecognised command. You get this NDR when

you make a typing mistake when you manually try to send email via telnet.

More likely, a routing group error, no routing connector, or no suitable address

space in the connector. (Try adding * in the address space)

This status code is a general error message in Exchange 2000. In fact Microsoft

introduced a service pack to make sure now get a more specific code.

.

5.1.x Problem with email address.

5.1.0 Often seen with contacts. Check the recipient address.

5.1.1

Another problem with the recipient address. Possibly the user was moved to

another server in Active Directory. Maybe an Outlook client replied to a message

while offline.

5.1.2

SMTP; 550 Host unknown. An error is triggered when the host name can’t be

found. For example, when trying to send an email to

bob@ nonexistantdomain.com.

[Example kindly sent in by Paul T.]

5.1.3Another problem with contacts. Address field maybe empty. Check the address

information.

5.1.4 Two objects have the same address, which confuses the categorizer.

5.1.5 Destination mailbox address invalid.

5.1.6

Problem with homeMDB or msExchHomeServerName - check how many users are

affected. Sometimes running RUS (Recipient Update Service) cures this problem.

Mailbox may have moved.

5.1.7 Problem with senders mail attribute, check properties sheet in ADUC.

5.2.x NDR caused by a problem with the large size of the email.

5.2.1The message is too large. Else it could be a permissions problem. Check the

recipient's mailbox.

5.2.2 Sadly, the recipient has exceeded their mailbox limit.

5.2.3 Recipient cannot receive messages this big. Server or connector limit exceeded.

5.2.4Most likely, a distribution list or group is trying to send an email. Check where the

expansion server is situated.

5.3.0Problem with MTA, maybe someone has been editing the registry to disable the

MTA / Store driver.

5.3.1 Mail system full. Possibly a Standard edition of Exchange reached the 16 GB limit.

5.3.2 System not accepting network messages. Look outside Exchange for a connectivity

problem.

5.3.3 Remote server has insufficient disk space to hold email. Check SMTP log.

5.3.4 Message too big. Check limits, System Policy, connector, virtual server.

5.3.5Multiple Virtual Servers are using the same IP address and port. See Microsoft

TechNet article: 321721 Sharing SMTP. Email probably looping.

5.4.0

DNS Problem. Check the Smart host, or check your DNS. It means that there is no

DNS server that can resolve this email address. Could be Virtual Server SMTP

address.

5.4.1 No answer from host. Not Exchange's fault check connections.

5.4.2 Bad connection.

5.4.3 Routing server failure. No available route.

5.4.4Cannot find the next hop, check the Routing Group Connector. Perhaps you have

Exchange servers in different Routing Groups, but no connector.

5.4.6

Tricky looping problem, a contact has the same email address as an Active Directory

user. One user is probably using an Alternate Recipient with the same email

address as a contact.

5.4.7 Delivery time-out. Message is taking too long to be delivered.

5.4.8Microsoft advise, check your recipient policy. SMTP address should be cp.com.

NOT server.cp.com.

5.5.0Underlying SMTP 500 error. Our server tried ehlo, the recipient's server did not

understand and returned a 550 or 500 error. Set up SMTP logging.

5.5.2Possibly the disk holding the operating system is full. Or could be a syntax error if

you are executing SMTP from a telnet shell.

5.5.3More than 5,000 recipients. Check the Global Settings, Message Delivery

properties.

5.5.5 Wrong protocol version

5.6.3 More than 250 attachments.

5.7.1

Permissions problem. For some reason the sender is not allowed to email this

account. Perhaps an anonymous user is trying to send mail to a distribution list.

Check SMTP Virtual Server Access Tab. Try checking this box: Allow computers

which successfully authenticate to relay

User may have a manually created email address that does not match a System

Policy.

5.7.2 Distribution list cannot expand and so is unable to deliver its messages.

5.7.3Check external IP address of ISA server. Make sure it matches the SMTP publishing

rule.

5.7.4 Extra security features not supported. Check delivery server settings

5.7.5 Cryptographic failure. Try a plain message with encryption.

5.7.6 Certificate problem, encryption level maybe to high.

5.7.7 Message integrity problem.

Mail Flow In Exchange Server 2003

MAPI client sends a message to a remote recipient. Information Store (Store.exe) receives the message. The created MailMsg object is forwarded to the Advanced Queue Engine (AQE). The Message Categorizer from the AQE processes the MailMsg object and splits it into MIME or RTF as necessary. The Message Categorizer expands groups and checks defined Message limits on Exchange. The MailMsg object is then transferred to the Remote Destination Domain within the AQE. The AQE passes the destination address to the Exchange Routing Engine. SMTP initiates an SMTP session with the remote SMTP host. After the SMTP session with the remote host has been established, the information store retrieves the body of the

message and converts the message as necessary. SMTP sends the Message from the Queue to the Remote Host.

De-fragmentation In Exchange Server 2003

Exchange runs defragmentation at 2:00 AM every day by default. This Online defragmentation is automatically run

as part of the database maintenance process. It release free space to the operating system by removing obsolete

objects and improve exchange performance. The online de-fragmentation process provides more database space

without changing the file size of the database.

Microsoft recommends running offline defragmentation for reducing the size of your exchange database file.

Offline defragmentation copy old database files to a new location, creates a new database and delete the old

database. As it copies the database file, so it needs free space and plus 10% than the original database file. Run

offline de-fragmentation after moving a large number of users.

Earlier Exchange corrupt database files after defragmentation. But later version, like Exchange 2000 or Exchange

2003 face very little problem of database corruption. As a precaution measure, take Exchange back up before

running offline defragmentation.

White Spacing in Exchange Server 2003

Exchange Server stops functioning once disk is out of space. Event ID 1221 in the Application log can be used to

check the recyclable space or ESEUTIL command can also display more details about the recyclable space.

Event ID 1221 display the rough estimate of recyclable space in the database after offline defragmentation. There

are some controversy around Event ID 1221 that if it includes EDB or STM or both. But it seems that this event only

counts EDM file.

Executing Eseutil.exe /MS database.edb command display a more accurate figure of recyclable space found in the

store if run on un-mounted store.

“SLV SPACE DUMP” section display information about the STM file. Multiply the value of “Free” with 4096 bytes

and you will get the size of recyclable space in the STM file.

Second section “SPACE DUMP” provides information about the EDB file. Multiply the number in “Available”

column by 4096 bytes to receive the size of the recyclable space in the EDB file.

Performance Monitor can be used to measure the size of the recoverable items with counter “Total Size of

recoverable Items”.

Monitoring and Status in Exchange Server 2003

Monitoring and Status

This utility is found in Exchange System Manager. It will send an email notification message when predefined

counters will reach up to some level. For example, if any window service is shutting down, an email alert message

will be send to the specified user.

Following things can be monitored from this feature:

Available virtual memory - the percentage of virtual memory that is presently available. CPU utilization - the percentage of CPU time that is presently in use. Free disk space - the amount of disk space, in megabytes (MB) that is available for use on this drive. SMTP queue growth - the number of minutes that the current queue has grown continuously. Windows 2000 service - various services running on the Exchange server. X.400 queue growth - the number of minutes that the current queue has grown continuously.

It is better to configure monitoring notifications from another Exchange server in the organization, instead

of having the server monitor itself. If the Exchange server changes to a state that requires that a

notification be sent, a server that is monitoring itself may not be able to deliver the message correctly if

the change in state was caused because a service related to Exchange services stopped.

Exchange is concerned enough about itself that, by default, it is automatically monitoring things that you probably never even thought about. A group of six critical (read: Exchange depends on them for its proper operation) services are monitored by Exchange. These six critical services are:

Exchange Information Store - manages Microsoft Exchange Information Storage. Exchange MTA Stacks - provides Microsoft Exchange X.400 services. Exchange Routing Engine - processes Microsoft Exchange routing information. Exchange System Attendant - provides system related services for Microsoft Exchange. Simple Mail Transfer Protocol (SMTP) - transports electronic mail across the network. World Wide Web Publishing Service - provides Web connectivity and administration through the Internet

Information Services snap-in.

Steps:-

1. Configure Notification tab to tell which server will be monitored, notification state and to whom mail will be sent

2. Then configure status tab where resources will be set with threshold limits.

How to configure Notification feature:

1. Open the Exchange System Manager from Start > Programs > Microsoft Exchange > System Manager.

2. Expand Tools > Monitoring and Status.

3. Right-click on Notifications > New >E-mail notification. (Figure-1)

Figure-1 Monitoring and Status

4. Click on Select to select your Exchange Server.

5. Select notification state under “Notify when monitored items are in” column. There will be two

notification states :

· Warning state

· Critical state

6. Click on To button to enter the email address of person who will receive the notification mail.

Figure-2 Monitoring and Status Properties

How to configure Status feature:

1. Exchange Server name will be displayed on the right-hand side in Status pane.

2. Right click on your exchange server and open its Properties.

Figure-3 Monitoring and Status Properties

3. Click on Add to add the resources.

Figure-4 Monitoring and Status Resources

4. Select the desired counter, for example, CPU Utilization.

Figure-5 Monitoring and Status CPU Utilization

Enter the duration and set the Warning and Critical state of CPU.

User (configured on Notification tab) will get a notification mail when specified counters will reach at Warning or

Critical State depending upon the reporting state.

You can use the Status tab properties to check the threshold limits and their status. In this window pane, you can

see a red-cross mark, which means that this service is stopped and mail will be sent to the specified user.

Figure-6 Monitoring and Status Resources

Monitoring Exchange Server 2003 Performance

Exchange Server comes with several Performance Monitor counters that, when used over time, can help you to spot trends in increased server usage. Below, I’ve listed some of these counters and what they mean. Remember that Performance Monitor is divided into objects and counters. The objects are basically categories, while counters measure a specific attribute of the object. In the list below, I’ve listed the object and counter in the format Object | Counter.

· MSExchangeIS | User Count: This counter represents the number of clients connected to the Exchange server. If you watch this counter over time, you can see how quickly the user count is increasing.

· MSExchangeIS | Active User Count: Sometimes the number of connected users can be deceptive when measuring the server’s workload. After all, how many users do you know who log in every morning and don’t actually do anything for most of the day? Any managers come to mind? If you want to look at the real load on the server, check out this counter. It counts only the users who’ve actually done something Exchange-related in the past 10 minutes.

· MSExchangeISPrivate | Message Recipients Delivered / min: This counter tracks the number of messages that are delivered by the private information store each minute. It may seem like common sense that the number of messages submitted should be the same as the number of messages delivered, but this isn’t the case. The number of messages delivered will usually be a lot higher because often a single message is sent to many different users.

· MSExchangeISPrivate | Messages Submitted / min: This counter measures the number of messages that are sent to the private information store each minute.

· MSExchangeISPublic | Messages Submitted / min: This counter measures the number of messages being sent to the public information store each minute.

· MSExchangeISPublic | Message Recipients Delivered / min: This counter measures the number of messages delivered by the public information store each minute. Like its private information store counterpart, this counter will be higher than the number of messages submitted because many messages are sent to multiple users.

· MSExchangeMTA | Messages / sec: This counter tallies the number of messages that flow through the MTA each second. This is a great counter for measuring the server’s overall workload.

· MSExchangeMTA | Messages Bytes / sec: If you notice that Exchange is bogging down over time, but the same number of users are sending about the same number of messages over that time period, then the slowdown could be caused by the messages getting bigger. You can use this counter to measure the number of bytes flowing through the MTA each second. If you want to know the average message size, simply divide this byte count by the number of messages flowing through the MTA each second.

Below counters are used to get some measureable statistics about how the server is performing. Unfortunately, there’s no way to directly measure how responsive the Exchange server is to user requests. If you really want to find out how responsive the server is, simply ask the users who use it. But, if you really want some measurable statistics, there are some Performance Monitor counters that you can track over time to get a feel for how the server is performing. I’ve listed these counters below in the same format as I previously used.

· MSExchangeISPrivate | Send Queue Size: This counter measures the number of messages that are waiting to be sent. This number can be greater than zero during periods of heavy activity, but it should return to zero quickly after the period of heavy use has passed.

· MSExchangeISPrivate | Average Time for Delivery: This counter indicates the average amount of time that it takes the private information store to deliver messages. (in ms)

· MSExchangeISPublic | Send Queue Size: This counter measures how many messages are waiting to be sent to the public information store. Just like its private information store counterpart, this counter can be above zero during periods of heavy use, but it should return to zero quickly thereafter.

· MSExchangeISPublic | Average Time for Delivery: This counter provides an indication of how long it usually takes the public information store to deliver messages.

· MSExchangeMTA | Work Queue Length: You’ve seen that both the private and public information stores can measure the number of messages waiting for delivery. If you want to measure the number of messages that are waiting for delivery collectively, then you can use this counter. It looks at the number of messages in the MTA queue rather than basing its results on the private or the public information store queue.

SMTP Relay in Exchange Server 2003

Exchange Server 2003 Relaying

By-default, Exchange relays only within the local domain, means the exchange clients can send or receive mails

only within their local domain. If relay is enabled, exchange clients can send mails to other domain as well. The

Exchange SMTP service us used to send emails to other organization.

If external users get access to your SMTP server, then they may start forwarding millions of unsolicited emails to

internet which will generate a lot of internet traffic. These users will use your SMTP as a source of sending these

spam mails to large number of computers. This will adversely affect your internet bandwidth. And also your

Exchange server will be listed as ‘blacklisted’ in the list of open mail relays. Your domain name will be blacklisted

and no mail be send or received through your domain name.

This is called open relay or insecure relay where unscrupulous sender gets access to your SMTP and route large

volumes of spam mail to Internet.

Symptoms of Mail Relaying

· You won’t be able to send mail to an increasing number of domains.

· Users on other domain won’t be able to send mails to your domain.

· You will receive Non-Delivery Reports (NDRs)/ with an error code 5.0.0., 5.7.1, or 5.7.3.

· You will notice an increase in your disk space usage.

By clearing ‘Anonymous access’ checkbox will not only prevent relaying through your server, but it will also stop

mails coming from other domain. If we clear this check box, then other mail servers will need a username and

password to get authenticated from you exchange server. In real environment, it is not possible for all internet

mail servers to be authenticated from your server. In other words, no one will be able to send mails to your

domain.

How to check if relaying is enabled within the local domain

Use telnet command to send email to internal domain. If that mail is delivered, it means relaying to local domain is

enabled.

How to check if relaying is enabled to the external domain

Use telnet to send email to internet domain from your internal address. You will get an error message “Unable to

relay”.

The ‘Allow all computers which successfully authenticate to relay, regardless of the list above’ option is enabled

by default, which allows internal users to relay mail through your Exchange Server.

There are lots of websites on internet which can also be used to check if your Exchange server is relaying or not.

http://www.checkor.com/

http://www.abuse.net/relay.html

Network Questions

Well-known ports: 0-1023

Registered ports: 1024-49151

Dynamic, private ports: 49152-65535

Port Numbers:-

HTTP (Hyper Text Transfer Protocol) – 80 (TCP/UDP)

HTTPs (Secured) – 443

POP3 (Post Office Protocol) – 110 (TCP)

SMTP (Simple Mail Transfer Protocol) – 25 (TCP)

LDAP (Lightweight Directory Access Protocol) – 389

NNTP (Network News Transfer Protocol) – 119 (TCP/UDP)

DNS (Domain Name System)– 53 (TCP/UDP)

FTP (File Transfer Protocol) – 20 (data transfer)

FTP – 21 (control)

TFTP (Trivial File Transfer Protocol) – 69 (UDP)

SNMP (Simple Network Management Protocol) – 161 (UDP)

IP Address Range

Class First Binary Octet

IP Range Network IDs

Host IDs # of networks

# of addresses

Subnet Mask

A 0xxxxxxx 0-127 A b, c, d 27 = 128 224 = 16777216

255.0.0.0

B 10xxxxxx 128-191 a, b c, d 214 = 16384 216 = 65536 255.255.0.0C 110xxxxx 192-223 a, b, c d 221 =

209715228 = 256 255.255.255.

0

Private IP address Range

Class Start End # of addressesA 10.0.0.0 10.255.255.255 16,777,216B 172.16.0.0 172.31.255.245 1,048,576C 192.168.0.0 192.168.255.255 65,536

OSI (Open System Interconnection) Model:-

1. Physical Layer –

· Pins, Voltage

· Hubs, Repeaters, Hubs, Network Adapters

· Cables/Wires

· BITS

2. Data Link Layer

· MAC (Media Access Control)Address/ARP

· Switches/Bridges

· Frames

3. Network Layers

· IP Addresses

· Routers

· Packets

4. Transport Layer

· TCP (Connection-oriented protocol)

· UDP (Connection-less protocol)

· NetBEUI

· Segments

5. Session Layer

· Duplex (Half/Full)

· Data

6. Presentation Layer

· Data Format (Compression/Encryption)

· Data

7. Application Layer

· HTTP, FTP, SMTP

· Data

AD Relates Questions:

Requirements for installing Active Directory

FSMO (Flexible Single Master Operations) Role:-

· Schema Master role

· Domain Naming role

· PDC Emulator role

· Infrastructure role

· RID (Relative Identifier) role

Group Policy order:-

· Local

· Site

· Domain

· OU

Active Directory Structure:-

· Physical Structure – Domain controller, site

· Logical Structure - Domain, OU

Active Directory Partitions:-

· Domain partition

· Schema Partition

· Configuration Partition