FTP, Advanced

<< Click to Display Table of Contents >>

Navigation:  Using SyncBackPro > Expert Mode >

FTP, Advanced

Previous pageReturn to chapter overviewNext page


Port: The port number of the FTP server. Most FTP servers use port 21, except when using Implicit SSL/TLS encryption in which case most FTP servers use port 990. Most SFTP servers users port 22. If you set the port number to zero then the default port will be used based on the settings.


Reconnect Attempts: Whenever the connection to the FTP server is lost, for whatever reason, SyncBackPro will reconnect and resume from where it left off. This is done in the background and does not require any user intervention. This setting specifies the number of attempts SyncBackPro should make to reconnect to the FTP server before it gives up. Note that this number refers to sequential attempts, not the total number of attempts that may be made over the entire profile run (i.e. once a reconnection is made the attempt counter is reset back to zero). This value is also used for the initial connection attempt, so if it is set to 1, and no connection can be made, then the profile will fail instead of trying again.


Seconds Between Attempts: The number of seconds SyncBackPro should pause before making another attempt to reconnect to the FTP server.


Read timeout (seconds): In some situations, e. g. when the connection is dropped, an FTP server may not respond to requests from SyncBackPro. This setting tells SyncBackPro how long to wait (in seconds) for an answer from the server whenever one is required. By default SyncBackPro will wait for 60 seconds before disconnecting and reconnecting to try again.


Scan threads: When SyncBack scans an FTP server, to see what files and folders are there, it does it one folder at a time on a single connection. This reduces the load on the FTP server, and in some cases, FTP servers only allow one connection at a time from a user. However, if you are allowed multiple simultaneous connections to an FTP server, and server load is not an issue, then you can configure SyncBack to use multiple connections to scan the FTP server. This can drastically reduce the scanning time, but results can vary. You will get the best results when you have multiple folders. Multi-threaded FTP scanning will not improve performance if you are only scanning the contents of one folder that only contains files. The maximum number of threads is 32.


Worker threads: Performance can be significantly improved by using multiple worker threads. A worked thread is basically another connection to the FTP server which is used to delete, upload and download files in parallel (at the same time). It does not upload or download large files using multiple connections (e.g. as done with some cloud storage services). Instead, it will upload or download multiple files at the same time (with each upload/download using one thread). Note that increasing this value too high can slow down the profile. It is also likely that the FTP server has a limit on the number of connections a user can have. Note that in some circumstances SyncBackPro will not use worker threads, e.g. if runtime scripts are used.



CompleteFTP (Professional and Enterprise Editions V12.1.0 or newer) includes a feature to enable single-call directory scanning (see the Folder-tree file setting in the Details section of CompleteFTP). SyncBackPro will automatically use this feature if it is available, resulting in considerably faster scanning of the FTP server.



Concurrent Download


If you are using the Eldos FTP Engine, and are not using SFTP, then you can use concurrent downloads. If the Threads value is greater than 1 then files larger than the Minimum size will be downloaded using multiple threads. This feature is useful when downloading multiple large files. This setting is different from Worker threads as that downloads multiple files at the same time where as this setting downloads a single large file using multiple threads. If concurrent downloads is used along with worker threads then files that will be downloaded concurrently will not be downloaded in worker threads. Note that this feature may not improve performance and may actually reduce it. It is only useful where the FTP server limits the outgoing bandwidth per connection.


Threads: The number of concurrent threads to use. The minimum and default value is 1 (meaning concurrent downloads will not be used), with the maximum being 10.


Minimum size: Files this size or larger (MBytes) will be downloaded concurrently. The minimum and default value is 5.



Encryption and compression options


Note than none of these options are available when using an SFTP server as they are not applicable.


Encrypt the communication channel: If enabled the communication channel will be encrypted (FTPS). This means that all commands sent to and received from the server will be encrypted, e.g. the password is encrypted. Note that this does not encrypt any file communication. For that you need to enable the option Encrypt the data channel. If the FTP server does not support encryption then this option and all the encryption settings are ignored.



If you're using FTPS with a scheduled profile then the schedule must be set to use a password.


Client certificate to use: If FTP encryption is being used then you can use this setting to specify which certificate SyncBack should use (or if one should be used at all). The certificate list is taken from the Personal certificates installed on the computer.


Encrypt the data channel: If enabled the data channel will also be encrypted. Note this will significantly slow down the profile. For the data channel to be encrypted you must have the communication channel encrypted.


Use implicit connection (port 990): If enabled an implicit SSL connection will be made (most FTP servers use port 990 for implicit connections). If disabled, an explicit SSL connection is made (most FTP servers use the standard FTP port 21 for explicit connections). This option is not available when using an SFTP server.


Do not fallback to an unencrypted connection: By default if SyncBack cannot connect to the FTP server using an encrypted connection then it will fallback to an unencrypted connection. However, if you want the connection to only be encrypted then enable this option.


Reduce bandwidth by using compression (MODE Z): To increase performance on slower networks enable this option. It will transmit data to and from the server in compressed form to reduce the send and receive time. Note that this option requires that the FTP server supports the MODE Z FTP extension. If not, this option will be ignored. Also note that enabling this option when the FTP server is on a LAN will actually decrease performance.


SFTP Host Key: If you are using an SFTP server (sbpro-feature-16x16 Pro version only) then this is the MD5 fingerprint of the servers public key (it is not the public key related to your login private key ). If you have the servers public key then you can load it to have it set. If you do not have the servers public key (which is normally the case) then you can click the Test FTP settings button and accept the public key that is received from the SFTP server. Whenever you connect to the SFTP server then SyncBackPro will check to make sure that the public key received by the SFTP server is the one expected. If not you will be prompted to either accept it or not. If the profile is run unattended then the profile will abort if they do not match. If you have not set a public key then the profile will prompt, or if run unattended it will continue running the profile. If you have the servers public key in a file then you can load it by clicking the folder icon. It is important to remember that this public key (the host identity key) is not related to the private key or user specific. All users connecting to the SFTP server get the same public key from the server. Please see the SFTP and Keys section for more details.



Note that DSA public keys over 1024 bits in size are not supported. RSA keys of up to 4096 bits are supported. If your SFTP server is using a DSA key over 1024 bits in size then enable the setting If the DSA key is too large to verify then silently accept it.





Limit bandwidth usage to…: This option lets you restrict the amount of bandwidth used for the FTP connection. For example, you may also be using the network for other things the same time the profile is run and do not want the profile to use all available bandwidth on the network. The option is not available for all FTP engine types.


Quote Character: If your FTP server supports wrapping quotes around filenames, e.g. if they have spaces, then enter the quotation character here. If your FTP server does not require or support quoting (most do not) then leave this empty. In most cases uses any value here will cause problems. This option is not available when using SFTP.


Server timezone: If the FTP server is in a different timezone then enter the number of minutes difference from GMT/UTC, e.g. +120 (meaning 120 minutes ahead of GMT/UTC), -60 (meaning 60 minutes behind GMT/UTC). SyncBackPro will ignore this setting if the FTP server reports the timezone it is in. However, you can force SyncBackPro to use this setting by prefixes an exclamation mark, e.g. !+120. Generally you do not need to enter a value, but in case the FTP server is incorrectly changing the date & times of files then you can correct it here. This option is not relevant and is ignored if your FTP server supports the MFMT or SITE UTIME extensions. See also the MDTM syntax and Self-correct settings. This option is not available when using SFTP.


Use Unicode (UTF8): This setting tells SyncBackPro to either use or not use the UTF8 extension on the FTP server. Some FTP servers do not correctly support UTF8 so you may wish to tell SyncBackPro not to use it. Also, some FTP servers do support it but don't tell FTP clients that they can and do support it.


MDTM syntax: In most situations it's best to leave this setting as Default. However, some FTP servers may require that a different command format be used. The MDTM command is used to set the last modification date & time of a file on the FTP server. This option is not relevant and is ignored if your FTP server supports the MFMT or SITE UTIME extensions. See also the Server timezone and Self-correct settings. This option is not available when using SFTP.


Do not use MLST and instead use LIST (not recommended): Modern FTP servers support more advanced methods of returning directory listings (via the MLST command). Such listings have a defined format that is designed for machine parsing. Older FTP servers often only support the old method of returning directory listings (via the LIST command, which is designed to be human readable and so is difficult to parse and often contain less information). In rare cases the output from the MLST command is invalid or corrupted and so cannot be used by SyncBack. If so, try enabling this option (and also see the following two settings). This option is not available when using SFTP.


Use custom LIST command (not used if server uses MLST): When requesting directory listings from the FTP server, and the LIST command is being used, then you can optionally define the LIST command to be sent to the FTP server. By default the command is LIST -la. This option is not available when using SFTP. When using DevArt this must be the parameters to send to the LIST command and cannot be a different FTP command. If the custom command you use is prefixed by LIST then it will be automatically removed. For example, if you use the custom command XYZ -123 then LIST XYZ -123 is sent to the FTP server.


Use alternative file list parser: If SyncBackPro is unable to parse the directory listings, e.g. the FTP server is old or rare, then try enabling this option. If enabled SyncBackPro will try other parsers to see if it can read the directory listings. It will also use the Server timezone setting with any file modification dates & times (unless MLST is being used). This option is not available when using SFTP.


Self-correct when setting a files date and time: Unfortunately many FTP servers do not set the correct date & time of a file, e.g. they incorrectly assume the date & time given to them is a local date & time. To avoid these kinds of problems you can ask SyncBackPro to check to see if the server is setting the dates & times correctly, and if not, to compensate. Note, however, that this is not always possible (it will not work on some old or basic FTP servers).


Server requires Allocate command: Some (old) FTP servers require that the FTP client reserve disk space before transferring files to the server. In general, the majority of FTP servers do not require or support this. This option is not available when using SFTP.


Force binary transfers: To increase performance SyncBackPro will not tell the FTP server it wants to transfer files in binary mode before every file is transferred. If this option is not enabled (default) then it will tell the FTP server to use binary mode immediately after the connection is made, and it will not tell it again. If this option is enabled then SyncBackPro will force the FTP server into binary mode before every file transfer. This will increase profile run times but may be required for some FTP servers. This option is not available when using SFTP.


Use the HOST command as this is a virtual host: Some FTP servers, usually when using the Microsoft IIS FTP server, are virtual hosts, meaning the server hosts multiple web sites. In this case, when SyncBackPro connects to the server it needs to tell the FTP server which host it needs to use (by using the HOST command). By default, this option is not enabled, and if it is enabled, and the server is not a virtual host, then it may stop SyncBackPro from connecting. This option is not available when using SFTP.


Automatically translate invalid filenames: By default SyncBackPro will translate filenames so they are compatible with Windows file systems. See this section for details.




All Content: 2BrightSparks Pte Ltd © 2003-2021