Netgear UTM25-100NAS User Manual

10-4

Network and System Management

If you want to reduce traffic by preventing undesired e-mails from reaching their destinations or by 
preventing access to certain sites on the Internet, you can use the UTM’s content filtering feature. 
By default, this feature is disabled; all requested traffic from any Web site is allowed with the 
exception of Web content categories that are mentioned in 

•

E-mail Content Filtering. To reduce incoming e-mail traffic, you can block e-mails with 
large attachments, reject e-mails based on keywords, file extensions, or file names, and set 
spam protection rules. There are several ways you can reduce undesired e-mail traffic:

–

Setting the size of e-mail files to be scanned. Scanning large e-mail files requires 
network resources and might slow down traffic. You can specify the maximum file or 
message size that is scanned, and if files that exceed the maximum size are skipped (which 
might compromise security) or blocked. For more information, see 

.

–

Keyword, file extension, and file name blocking. You can reject e-mails based on 
keywords in the subject line, file type of the attachment, and file name of the attachment. 
For more information, see 

.

–

Protecting against spam. Set up spam protection to prevent spam from using up valuable 
bandwidth. For more information, see 

•

Web Content Filtering. The UTM provides extensive methods to filtering Web content in 
order to reduce traffic:

–

Web category blocking. You can block entire Web categories because their content is 
undesired, offensive, or not relevant, or simply to reduce traffic. For more information, see 

–

Keyword and file extension blocking. You can specify words that, should they appear in 
the Web site name (URL), file extension, or newsgroup name, cause that site, file, or 
newsgroup to be blocked by the UTM. For more information, see 

–

URL blocking. You can specify up to 200 URLs that are blocked by the UTM. For more 
information, see 

–

Web services blocking. You can block Web services such as instant messaging and peer-
to-peer services. For more information, see 

.