Time to time I see people get surprised when I tell them Iranian software developers have not access to international job market and can not have global clients easily.
It's a long time that Iran is under US and international sanctions due to political issues. As a result foreign employers especially US based companies are not legally allowed to employ Iranian developers because paying them and having business relations is forbidden.
Some web sites like ThemeForest.com (An online market for HTML themes and other materials) does not allow browsing their websites inside Iran. They explicitly stated that their site is not available in countries like Iran.
Some other marketplaces does not have Iran in their registration forms fields. You are forced to select another country instead of Iran. An example is upwork.com.
Some other websites have no problem until payments. They need a copy of Passport or a proof of address that obviously would cause problems if you are from Iran. Another problems raises when you want to use PayPal to transfer money. PayPal is based in US.
One of my friend that was working in a freelancing website told me that he had trouble transferring money to Iran. He used a bureau de change via Dubai, UAE to transfer his own money to Iran. A noticeable commission applied to this transfer.
One another friend that wanted to be employed as a remote member of western software development company said everything went OK with the interview. They were satisfied with his skills but when they realized he is Iranian, process stopped.
There also problems getting service from none job websites like Google Developers (formerly Google Code) or Oracle. They do not allow Iranians to use their services.