diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index f80444e4..1af62ca4 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -1050,7 +1050,7 @@ class HttpCli(object):
                     if not bos.path.isdir(fdir):
                         raise Pebkac(404, "that folder does not exist")
 
-                    suffix = ".{:.6f}-{}".format(time.time(), self.ip)
+                    suffix = "-{:.6f}-{}".format(time.time(), self.dip)
                     open_args = {"fdir": fdir, "suffix": suffix}
                 else:
                     open_args = {}
diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index dfcbf850..41e54414 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -1318,7 +1318,7 @@ class Up2k(object):
 
         # TODO broker which avoid this race and
         # provides a new filename if taken (same as bup)
-        suffix = ".{:.6f}-{}".format(ts, ip)
+        suffix = "-{:.6f}-{}".format(ts, ip.replace(":", "."))
         with ren_open(fname, "wb", fdir=fdir, suffix=suffix) as f:
             return f["orz"][1]
 
@@ -1877,7 +1877,8 @@ class Up2k(object):
                 del self.registry[job["ptop"]][job["wark"]]
             return
 
-        suffix = ".{:.6f}-{}".format(job["t0"], job["addr"])
+        dip = job["addr"].replace(":", ".")
+        suffix = "-{:.6f}-{}".format(job["t0"], dip)
         with ren_open(tnam, "wb", fdir=pdir, suffix=suffix) as f:
             f, job["tnam"] = f["orz"]
             if (