Custom URL profile field, I need help

[TAMAN]

i want to create a custom url profile field and to display the input as a custom text

i have tried like this

<a href="{content}" rel="external">url</a>

but at profile when i click the link it goes to another page says

 

Quote

 

Not Acceptable!

An appropriate representation of the requested resource could not be found on this server. This error was generated by Mod_Security

 

what is Mod_Security? is it because i have enabled mod_security where can i disable it and is it ok if i disable it?

[TAMAN]

I will add another question

i want to create a custom profile field if member fills out a name for example "BARZANY"  

the name will be added at the end of this link

http://battlelog.battlefield.com/bf4/user/

it will be like this http://battlelog.battlefield.com/bf4/user/BARZANY

i know its possible because i have seen it i just dont know how they do that.

so basically i want to create a custom profile field to show at topics under user info.

for example i want the field to show like this

BF4 Name: BARZANY

when member fill out their bf4 user name for example BARZANY, the name will be linked to their bf4 profile