Bug#841531: openssh-client: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

[Martin-Éric Racine <martin-eric.racine@iki.fi>]

Package: openssh-client
Version: 1:7.3p1-1
Severity: important

Unable to negotiate with 172.16.1.254 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

I get the above error when trying to connect to a router using openssh-client from Testing.

Connecting using the openssh-client from Stable works as expected.

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (1011, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.7.0-1-amd64 (SMP w/1 CPU core)
Locale: LANG=fi_FI.UTF-8, LC_CTYPE=fi_FI.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages openssh-client depends on:
ii  adduser           3.115
ii  dpkg              1.18.10
ii  libc6             2.24-3
ii  libedit2          3.1-20150325-1+b1
ii  libgssapi-krb5-2  1.14.3+dfsg-2
ii  libselinux1       2.5-3
ii  libssl1.0.2       1.0.2j-1
ii  passwd            1:4.2-3.2
ii  zlib1g            1:1.2.8.dfsg-2+b1

Versions of packages openssh-client recommends:
ii  xauth  1:1.0.9-1

Versions of packages openssh-client suggests:
pn  keychain      <none>
pn  libpam-ssh    <none>
pn  monkeysphere  <none>
pn  ssh-askpass   <none>

-- no debconf information