What is the best way to screen for natural amino acid peptides of about 8 residues that bind specifically to the Fc region of mouse IgG2b?

The amino acid sequence of the Fcr region of mouse IgG2b and PDB data were obtained here.

https://www.ncbi.nlm.nih.gov/Structure/mmdb/mmdbsrv.cgi?Dopt=s&uid=154655

The PepComposer I looked into seemed to best meet my objectives.

https://pubmed.ncbi.nlm.nih.gov/27131789/

However, this server does not appear to be operational at this time.

How can I find in silico peptides that binds specifically to the Fc region of mouse IgG2b?