Support different ipv6 network device in network-tunnel-manager.sh by heri16 · Pull Request #6255 · nymtech/nym

heri16 · 2025-11-29T18:11:48Z

On many VPS providers, the IPv4 uplink network interface is eth0, while the IPv6 uplink may be on a different interface (e.g., eth1 or another device).

This PR:

Improves automatic detection of the uplink network interface for both IPv4 and IPv6.
Adds support for configurations where the IPv4 and IPv6 uplinks are on different interfaces, while remaining fully compatible with setups where they share the same interface.
Change the expected environment variable name from NETWORK_DEVICE to IPV4_UPLINK_DEV and IPV6_UPLINK_DEV
Add CLI flag for --uplink-dev-v6

This change is

vercel · 2025-11-29T18:11:56Z

@heri16 is attempting to deploy a commit to the nyx-network Team on Vercel.

A member of the Team first needs to authorize it.

github-actions · 2025-11-29T18:11:57Z

Thank you for making this first PR

serinko · 2025-12-02T12:39:49Z

Hey, it looks good. Thank you for your PR.
You haven't ticked the env var but I see it added in the PR

Please redirect it from develop to feat/operators/ntm-upgrades.

This var is used here:
https://github.com/nymtech/nym/blob/develop/scripts/nym-node-setup/nym-node-cli.py#L578
https://github.com/nymtech/nym/blob/develop/scripts/nym-node-setup/nym-node-cli.py#L643

If you want you can toggle that too, otherwise I will fix that one

heri16 · 2025-12-02T20:29:38Z

For the record:
"ip -6 -o route show default" was not reliable.
On my VPS machine (Debian 13), it requires "print $3" while the original script uses "print $5".
See:

nonroot@localhost:~$ ip -6 -o route show default
default dev eth1.1 proto static metric 1024 pref medium

heri16 · 2025-12-02T20:35:21Z

https://github.com/nymtech/nym/blob/develop/scripts/nym-node-setup/nym-node-cli.py#L643

Should we have:

Option A: --uplink-dev-v4 and --uplink-dev-v6
Option B: --uplink-dev and --uplink-dev-v6 where v6 defaults to autodetection if unspecified?

@serinko

Also, I've found another issue with the quic_bridge_deployment.sh on machines such as mine.
Would you prefer a different PR? This line containing UPLINK_DEV is used by quic_bridge_deployment.sh: https://github.com/nymtech/nym/blob/develop/scripts/nym-node-setup/nym-node-cli.py#L577

…dge_deployment.sh

heri16

Please review latest changes to this PR.

heri16 · 2025-12-02T21:52:42Z

serinko · 2025-12-03T09:13:30Z

I would prefer this one as the program should ask minimum from the operator

* Option B: `--uplink-dev` and `--uplink-dev-v6` where v6 defaults to autodetection if unspecified?

If that issue on QUIC connects to this interface, feel free to add it to this PR.

vercel · 2025-12-03T09:14:49Z

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heri16 · 2025-12-05T21:10:06Z

Done. Please review and merge. @serinko @mfahampshire

serinko · 2025-12-10T15:37:03Z

scripts/nym-node-setup/network-tunnel-manager.sh

  local dev

-  dev="$(eval "$cmd" 2>/dev/null | awk '{print $5}' | head -n1 || true)"
+  ip="$(getent ahosts${1//-/v} "$host" 2>/dev/null | awk '$2=="STREAM" {print $1}' | head -n1 || true)"


Does this work?

Imo it returns: getent ahostsv4 "$host" I would expect you want some of this syntax to be returned:

getent ahosts -4 "$host" # or getent ahosts -6 "$host"

Hence smth like:

detect_uplink_interface() { local aflag="$1" # -4 or -6 local host="$2" local ip dev # Resolve host to IP for the requested address family ip="$(getent ahosts "$host" "$aflag" 2>/dev/null | awk '$2=="STREAM" {print $1}' | head -n1 || true)" if [[ -z "$ip" ]]; then return 1 fi # Find which interface would be used to reach that IP dev="$(ip "$aflag" -o route get "$ip" 2>/dev/null | awk '{print $5}' | head -n1 || true)" if [[ -n "$dev" && "$dev" =~ ^[a-zA-Z0-9._-]+$ ]]; then echo "$dev" return 0 fi return 1 }

and later on

# uplink device detection, can be overridden IPV4_UPLINK_DEV="${IPV4_UPLINK_DEV:-}" if [[ -z "$IPV4_UPLINK_DEV" ]]; then IPV4_UPLINK_DEV="$(detect_uplink_interface -4 "ifconfig.co" || true)" fi if [[ -z "$IPV4_UPLINK_DEV" ]]; then error "cannot determine ipv4 uplink interface. set IPV4_UPLINK_DEV" exit 1 fi IPV6_UPLINK_DEV="${IPV6_UPLINK_DEV:-}" if [[ -z "$IPV6_UPLINK_DEV" ]]; then IPV6_UPLINK_DEV="$(detect_uplink_interface -6 "ifconfig.co" || true)" fi if [[ -z "$IPV6_UPLINK_DEV" ]]; then error "cannot determine ipv6 uplink interface. set IPV6_UPLINK_DEV" exit 1 fi

Yes, it's tested to be working.
It's either getent ahostsv4 or getent ahostsv6.

See:

nonroot@nymExitNode:~$ getent ahosts -4 "proof.ovh.net" getent: invalid option -- '4' Try `getent --help' or `getent --usage' for more information. nonroot@nymExitNode:~$ getent ahostsv4 "proof.ovh.net" 141.95.207.211 STREAM proof.ovh.net 141.95.207.211 DGRAM 141.95.207.211 RAW

serinko · 2025-12-10T15:38:40Z

scripts/nym-node-setup/network-tunnel-manager.sh

@@ -194,11 +201,11 @@ fetch_ipv6_address() {

 fetch_and_display_ipv6() {
  local ipv6_address


did you have time to test this if in case of ip4 and ipv6 devices == it prints the correct stuff?

Yes, I've tested it. fetch_and_display_ipv6 only prints ipv6 address as it should.

See:

nonroot@nymExitNode:~$ sudo ./network-tunnel-manager.sh fetch_and_display_ipv6 ----- 2025-12-11 01:27:00 START network-tunnel-manager ----- Logs are being saved locally to: /var/log/nym/network_tunnel_manager.log These logs never leave your machine. [2025-12-11 01:27:00] COMMAND: fetch_and_display_ipv6 ARGS: fetch_and_display_ipv6 [OK] ipv6 address on eth0.2: 2a07:b944::2:2/128 Logs saved locally at: /var/log/nym/network_tunnel_manager.log [OK] operation fetch_and_display_ipv6 completed

serinko · 2025-12-10T15:39:43Z

I looked at it and it looks good, though there are two comments.

Then I need to test it, which I will only get to after Ansible playbooks out and implementation of NIP-4,5&6.

I would expect it in production after new year.

heri16 · 2025-12-10T18:36:54Z

Updated code applying feedback from comments. Ready for review. @serinko @mfahampshire

benedettadavico · 2026-02-11T14:31:32Z

@serinko to review this again please

Support different ipv6 network device in network-tunnel-manager.sh

1ed0de7

Fine tune network-tunnel-manager.sh

86f1307

heri16 changed the base branch from develop to feat/operators/ntm-upgrades December 2, 2025 20:37

heri16 added 3 commits December 3, 2025 03:57

Change env variable NET4_DEVICE to IPV4_UPLINK_DEV

865707b

Add uplink_dev_v4 and uplink_dev_v6 flag to nym-node-cli.py

f80a464

Add --uplink-dev-v4 and --uplink-dev-v6 flag to nym-node-cli

ca44c49

heri16 requested a review from mfahampshire as a code owner December 2, 2025 21:08

Use IPV4_UPLINK_DEV and IPV6_UPLINK_DEV env variables in quic_bri…

46eead6

…dge_deployment.sh

heri16 commented Dec 2, 2025

View reviewed changes

serinko self-requested a review December 3, 2025 09:14

serinko added this to the Independent Release milestone Dec 3, 2025

change --uplink-dev-v4 flag to --uplink-dev

e3f2636

serinko requested changes Dec 10, 2025

View reviewed changes

Updated detect_uplink_interface in network-tunnel-manager.sh

3f2baa5

jstuczyn requested review from benedettadavico and tommyv1987 December 17, 2025 10:03

jstuczyn modified the milestones: Independent Release, Quark - (mainnet release 24th Feb) Feb 10, 2026

benedettadavico requested a review from serinko February 11, 2026 14:31

benedettadavico modified the milestones: Quark - (mainnet release 24th Feb), Raclette - (mainnet release 10th march) Feb 11, 2026

		@@ -194,11 +201,11 @@ fetch_ipv6_address() {

		fetch_and_display_ipv6() {
		local ipv6_address

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