Facing same kind of issue with a CentOS 6 client which can't clone one of our repositories:
# cat /root/.ssh/config
Host X.X.X.X
LogLevel DEBUG3
# git clone ssh://ovidiu....@X.X.X.X:29418/testing.git
Initialized empty Git repository in /tmp/testing/.git/
debug2: ssh_connect: needpriv 0
debug1: Connecting to X.X.X.X [X.X.X.X] port 29418.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/identity-cert type -1
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug3: Not a RSA1 key file /root/.ssh/id_dsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /root/.ssh/id_dsa type 2
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version GerritCodeReview_3.0.1 (SSHD-CORE-2.0.0)
debug1: no match: GerritCodeReview_3.0.1 (SSHD-CORE-2.0.0)
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug3: Wrote 864 bytes for a total of 885
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit:
ssh-rsa-...@openssh.com,
ssh-dss-...@openssh.com,
ssh-rsa-...@openssh.com,
ssh-dss-...@openssh.com,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,
rijnda...@lysator.liu.sedebug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,
rijnda...@lysator.liu.sedebug2: kex_parse_kexinit: hmac-sha1,
uma...@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,
hmac-ri...@openssh.com,hmac-sha1-96
debug2: kex_parse_kexinit: hmac-sha1,
uma...@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,
hmac-ri...@openssh.com,hmac-sha1-96
debug2: kex_parse_kexinit: none,
zl...@openssh.com,zlib
debug2: kex_parse_kexinit: none,
zl...@openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group18-sha512,diffie-hellman-group17-sha512,diffie-hellman-group16-sha512,diffie-hellman-group15-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha2-512,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha2-512,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-sha1
debug1: kex: server->client aes128-ctr hmac-sha1 none
debug2: mac_setup: found hmac-sha1
debug1: kex: client->server aes128-ctr hmac-sha1 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<2048<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug3: Wrote 24 bytes for a total of 909
debug2: dh_gen_key: priv key bits set: 163/320
debug2: bits set: 1023/2048
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: Wrote 272 bytes for a total of 1181
debug3: put_host_port: [X.X.X.X]:29418
debug3: put_host_port: [X.X.X.X]:29418
debug3: check_host_in_hostfile: host [X.X.X.X]:29418 filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: host [X.X.X.X]:29418 filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 26
debug3: check_host_in_hostfile: host [X.X.X.X]:29418 filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: host [X.X.X.X]:29418 filename /root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 26
debug1: Host '[X.X.X.X]:29418' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:26
debug2: bits set: 1039/2048
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: Wrote 16 bytes for a total of 1197
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug3: Wrote 52 bytes for a total of 1249
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /root/.ssh/identity ((nil))
debug2: key: /root/.ssh/id_rsa ((nil))
debug2: key: /root/.ssh/id_dsa (0x7f0e77b148c0)
debug2: key: /root/.ssh/id_ecdsa ((nil))
debug3: Wrote 84 bytes for a total of 1333
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/identity
debug3: no such identity: /root/.ssh/identity
debug1: Trying private key: /root/.ssh/id_rsa
debug3: no such identity: /root/.ssh/id_rsa
debug1: Offering public key: /root/.ssh/id_dsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug3: Wrote 532 bytes for a total of 1865
debug1: Server accepts key: pkalg ssh-dss blen 433
debug2: input_userauth_pk_ok: SHA1 fp c0:d7:f9:cc:6b:2b:37:35:97:53:79:d6:a5:49:3e:2b:31:09:73:60
debug3: sign_and_send_pubkey: DSA c0:d7:f9:cc:6b:2b:37:35:97:53:79:d6:a5:49:3e:2b:31:09:73:60
debug1: read PEM private key done: type DSA
debug3: Wrote 596 bytes for a total of 2461
debug1: Authentication succeeded (publickey).
debug2: fd 4 setting O_NONBLOCK
debug2: fd 5 setting O_NONBLOCK
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Entering interactive session.
debug3: Wrote 68 bytes for a total of 2529
debug2: callback start
debug2: client_session2_setup: id 0
debug1: Sending environment.
debug3: Ignored env HOSTNAME
debug3: Ignored env TERM
debug3: Ignored env SHELL
debug3: Ignored env HISTSIZE
debug3: Ignored env SSH_CLIENT
debug3: Ignored env SSH_TTY
debug3: Ignored env USER
debug3: Ignored env LS_COLORS
debug3: Ignored env MAIL
debug3: Ignored env PATH
debug3: Ignored env PWD
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug3: Ignored env HISTCONTROL
debug3: Ignored env SHLVL
debug3: Ignored env HOME
debug3: Ignored env GIT_SSH_COMMAND
debug3: Ignored env LOGNAME
debug3: Ignored env CVS_RSH
debug3: Ignored env SSH_CONNECTION
debug3: Ignored env LESSOPEN
debug3: Ignored env G_BROKEN_FILENAMES
debug3: Ignored env _
debug3: Ignored env OLDPWD
debug3: Ignored env GIT_DIR
debug1: Sending command: git-upload-pack '/testing.git'
debug2: channel 0: request exec confirm 1
debug2: fd 3 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 2097152 rmax 32768
debug3: Wrote 152 bytes for a total of 2681
debug2: channel_input_status_confirm: type 99 id 0
debug2: exec request accepted on channel 0
debug3: Wrote 260 bytes for a total of 2941
debug2: channel 0: window 1997355 sent adjust 99797
debug3: Wrote 52 bytes for a total of 2993
debug2: channel 0: window 1966080 sent adjust 131072iB/s
debug3: Wrote 52 bytes for a total of 3045
debug2: channel 0: window 1966080 sent adjust 131072iB/s
debug3: Wrote 52 bytes for a total of 3097
debug2: channel 0: window 1966080 sent adjust 131072iB/s
debug3: Wrote 52 bytes for a total of 3149
debug2: channel 0: window 1966080 sent adjust 131072iB/s
debug3: Wrote 52 bytes for a total of 3201
debug3: Wrote -1 bytes for a total of 3201
Write failed: Broken pipe