go proxy repo cannot download some packages

[kazimsarikaya]

my go proxy is configured as:

i am getting this error:

podman run -ti --rm docker.io/library/golang:1.26.5-alpine3.24
Trying to pull docker.io/library/golang:1.26.5-alpine3.24...
Getting image source signatures
Copying blob 4f4fb700ef54 skipped: already exists  
Copying blob 55afa1ecc21d skipped: already exists  
Copying blob cea3d467f844 done   | 
Copying blob 6563b0ba6ce9 done   | 
Copying blob 56bd32640bdf done   | 
Copying config 7849a63a4b done   | 
Writing manifest to image destination
/go # 
/go # cd
~ # go env -w GOPROXY=https://repo.example.com/repository/go-proxy/,direct
~ # go install golang.org/x/tools/gopls@latest
go: downloading golang.org/x/tools/gopls v0.23.0
go: downloading golang.org/x/tools v0.49.0
go: downloading golang.org/x/telemetry v0.0.0-20260625142307-59b4966ccb57
go: downloading github.com/modelcontextprotocol/go-sdk v1.6.0
go: downloading golang.org/x/sync v0.21.0
go: downloading golang.org/x/tools v0.47.1-0.20260707181000-a299dadba899
go: downloading golang.org/x/mod v0.37.0
go: downloading golang.org/x/vuln v1.4.0
go: downloading github.com/fsnotify/fsnotify v1.9.0
go: downloading github.com/google/jsonschema-go v0.4.3
go: downloading github.com/fatih/gomodifytags v1.17.1-0.20250423142747-f3939df9aa3c
go: downloading mvdan.cc/xurls/v2 v2.6.0
go: downloading honnef.co/go/tools v0.8.0-rc.1
go: downloading github.com/yosida95/uritemplate/v3 v3.0.2
go: downloading golang.org/x/text v0.38.0
go: downloading mvdan.cc/gofumpt v0.10.0
go: downloading golang.org/x/sys v0.46.0
go: downloading github.com/fatih/camelcase v1.0.0
go: downloading github.com/fatih/structtag v1.2.0
go: downloading golang.org/x/exp/typeparams v0.0.0-20260611194520-c48552f49976
go: downloading golang.org/x/oauth2 v0.36.0
go: downloading github.com/segmentio/encoding v0.5.4
go: downloading github.com/BurntSushi/toml v1.6.0
/go/pkg/mod/github.com/modelcontextprotocol/go-sdk@v1.6.0/internal/json/json.go:13:2: github.com/segmentio/encoding@v0.5.4: reading https://repo.example.com/repository/go-proxy/github.com/segmentio/encoding/@v/v0.5.4.zip: 400 Bad Request

at kkrepo's log there is:

2026-08-20T21:16:50.665Z  WARN 1 --- [kkrepo] [o-8080-exec-168] g.k.k.s.m.RepositoryRequestMetricsFilter : Repository request completed with non-success status: status=400 method=GET uri=/repository/go-proxy/github.com/segmentio/encoding/@v/v0.5.4.zip path=github.com/segmentio/encoding/@v/v0.5.4.zip params={} repo=go-proxy format=go type=proxy operation=go_zip route=repository user=anonymous userSource=Local remoteAddr=192.168.200.11 userAgent=Go-http-client/2.0 failure=none

this error not happens every packet. but especially this segmentio/encoding@v0.5.4 packet.

i encounter this problem with both 0.8.0 and 0.9.0 releases. i can install gopls@latest without proxy successfully.

thanks for helps.

[klboke]

@kazimsarikaya This is expected behavior for security reasons. kkRepo blocks cross-host redirects by default. In this case, proxy.golang.org redirects the ZIP download to storage.googleapis.com.

On v0.9.0, please add storage.googleapis.com to the Allowed redirect host field in the go-proxy repository settings, save the changes, and try again. Please let us know whether it works after that.

[kazimsarikaya]

yes it worked. now, new question, i see the field accepts only one redirect host. i expect google only uses one redirect host (an object storage service). but in generally, is it correct? can the field accept multiple hosts?

[klboke]

@kazimsarikaya Yes. Although the label is singular, the field supports multiple redirect hosts. Enter exact host names separated by commas, for example:

storage.googleapis.com, another-cdn.example.com

Up to 64 hosts are supported. Each entry must be a host name only—no scheme, port, path, or wildcard. For the proxy.golang.org download you reported, storage.googleapis.com is the only redirect host we observed. We recommend keeping the allowlist minimal and adding another host only after confirming that the upstream legitimately redirects to it.

[kazimsarikaya]

thanks for replies and this wonderful project 😍.