> For the complete documentation index, see [llms.txt](https://docs.verygoodsecurity.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verygoodsecurity.com/vault/iso-proxy.md).

# TCP Proxy (ISO8583)

VGS TCP Proxy allows filtering out sensitive data with binary protocols. TCP stands for Transmission Control Protocol, a network protocol used for secure transfer of data over the internet.

A common use case is transmitting data in the ISO8583 format, an international standard for financial transactions. This binary format can be processed via the VGS TCP Proxy. The proxy sits in front of incoming and outgoing TCP traffic and filters out sensitive data, such as the credit card number.

Sensitive data is replaced in transit with [aliases](https://www.verygoodsecurity.com/blog/posts/tokenization-vs-encryption-vs-aliasing-how-to-truly-minimize-compliance/) supplied by VGS. VGS ensures that all the checksum data is updated properly after a TCP stream has been modified.

For more details on the TCP Proxy, please contact us at <support@vgs.io>


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