Some doubts regarding Malwares and it's software user agents

[mandi]

I need to confirm or need answer for this question

when ever a Application (may be malwares like RAT,keylogger,shells,backdoors) from our pc connects to internet via a software/Application,does it emits any kind of user agents from the respective Application?

Also is it must for every Application to emit a "user agent"(it may be real or fake,it does not matter) from it's software, while a connection is made to the internet?

hope some one may clear my doubt....

[Herm1t]

You mean that does ur antivirus notices you about an application that is trying to connect to internet?

It depends what antivirus you use, the 2 i know of is: avira antivir premium and nod smart security does ask you about it.

I personally use avira premium, it asks you and even show u the portnumber.

[mandi]

NO not like that,any Application connecting to internet emits user agent or not?

is it must for an Application to emit a user agent while being connecting to internet?

that is my questions,hope you got it clear now..

[eax]

Well, only the browser 'emits' user agents'.