# Option to ipv6 in DNS lookup for backups

**URL:** <https://forums.foundationdb.org/t/option-to-ipv6-in-dns-lookup-for-backups/4114>\
**Category:** Running FoundationDB\
**Created:** [August 19, 2023, 5:37pm UTC](https://forums.foundationdb.org/t/option-to-ipv6-in-dns-lookup-for-backups/4114 "2023-08-19T17:37:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![larshagen](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/larshagen/32/776_2.png) [@larshagen](https://forums.foundationdb.org/u/larshagen)\
**Post date:** [August 19, 2023, 5:37pm UTC](https://forums.foundationdb.org/t/option-to-ipv6-in-dns-lookup-for-backups/4114/1 "2023-08-19T17:37:11Z")

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I am working on getting our FDB backup in Google Cloud Platform to work directly with Google Cloud Storage, instead of our current setup of using the deprecated Minio gateway.

One of our issues is the same as reported in [Fdbbackup not work with ipv6 resolver, work with ipv4](https://forums.foundationdb.org/t/fdbbackup-not-work-with-ipv6-resolver-work-with-ipv4/3694), only we don’t have an easy option to turn on ipv6.

The behaviour to prefer ipv6 seems to be introduced by [Prefer IPv6 in hostname resolving. by RenxuanW · Pull Request #7733 · apple/foundationdb · GitHub](https://github.com/apple/foundationdb/pull/7733), which was backported to 7.1.

Would it be possible to add a knob to prefer ipv4?

I have confirmed that I am able to talk to GCS if I do the DNS lookup manually and put the ipv4 address in `/etc/hosts`, but I don’t think that is good solution.

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**Author:** ![jamesreprise](https://sea1.discourse-cdn.com/foundationdb/user_avatar/forums.foundationdb.org/jamesreprise/32/1854_2.png) [@jamesreprise](https://forums.foundationdb.org/u/jamesreprise)\
**Post date:** [January 13, 2025, 9:53pm UTC](https://forums.foundationdb.org/t/option-to-ipv6-in-dns-lookup-for-backups/4114/2 "2025-01-13T21:53:05Z")

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This can be done now with `--knob_resolve_prefer_ipv4_addr=1` since [Add a knob RESOLVE\_PREFER\_IPV4\_ADDR to prefer IPv4 addresses [release-7.1] by jzhou77 · Pull Request #10826 · apple/foundationdb · GitHub](https://github.com/apple/foundationdb/pull/10826).