Re: slow ssh response time

hello mike,

Well normally DNS resolution slows any network activity down. Even in port s=
canning for example using nmap its prefered to use the -n switch to disable D=
NS resolution because it slows the scan down.=20

Hope this helped to clarify things a bit.=20

Regards,

Saif
OSCP

Sent from my iPhone.=20

On Apr 13, 2011, at 5:14 AM, "Michael Sioutis" <[email protected]> wrote:=


> Actually the problem seems to have been sorted out. Right after
> placing in the sshd_config file "UseDNS no" and reloading/restarting
> the OpenSSH server, no effect took place, but a few hours later my ssh
> response became instant (<1 sec) :)
> Strange..
>=20
> Mike
>=20
> On Tue, Apr 12, 2011 at 7:15 PM, Michael Sioutis <[email protected]> wr=
ote:
>> Hello!!
>>=20
>> I have a slow ssh response time and I don't know what is causing it.
>> I'm providing you with some information and kindly requesting
>> your help.
>>=20
>> ***System***
>> Linux  Ubuntu 10.04.2 LTS 2.6.32-30-generic #59-Ubuntu SMP Tue Mar 1
>> 21:30:46 UTC 2011 x86_64 GNU/Linux
>>=20
>> ***OpenSSH version***
>> OpenSSH_5.3p1 Debian-3ubuntu6, OpenSSL 0.9.8k 25 Mar 2009
>>=20
>> ***Problem***
>> ssh -v user@host
>> OpenSSH_5.5p1 Debian-4ubuntu5, OpenSSL 0.9.8o 01 Jun 2010
>> debug1: Reading configuration data /etc/ssh/ssh_config
>> debug1: Applying options for *
>> debug1: Connecting to host [XX.XXX.XX.XXX] port 22.
>> debug1: Connection established.
>> debug1: identity file /home/user/.ssh/id_rsa type 1
>> debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
>> debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
>> debug1: identity file /home/user/.ssh/id_rsa-cert type -1
>> debug1: identity file /home/user/.ssh/id_dsa type -1
>> debug1: identity file /home/user/.ssh/id_dsa-cert type -1
>>=20
>> --------------->Delay (4-5 secs)<---------------
>>=20
>> debug1: Remote protocol version 2.0, remote software version
>> OpenSSH_5.3p1 Debian-3ubuntu6
>> debug1: match: OpenSSH_5.3p1 Debian-3ubuntu6 pat OpenSSH*
>> debug1: Enabling compatibility mode for protocol 2.0
>> debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu5
>> debug1: SSH2_MSG_KEXINIT sent
>> debug1: SSH2_MSG_KEXINIT received
>> debug1: kex: server->client aes128-ctr hmac-md5 none
>> debug1: kex: client->server aes128-ctr hmac-md5 none
>> debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
>> debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
>> debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
>> debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
>> debug1: Host 'host' is known and matches the RSA host key.
>> debug1: Found key in /home/user/.ssh/known_hosts:9
>> debug1: ssh_rsa_verify: signature correct
>> debug1: SSH2_MSG_NEWKEYS sent
>> debug1: expecting SSH2_MSG_NEWKEYS
>> debug1: SSH2_MSG_NEWKEYS received
>> debug1: Roaming not allowed by server
>> debug1: SSH2_MSG_SERVICE_REQUEST sent
>> debug1: SSH2_MSG_SERVICE_ACCEPT received
>> debug1: Authentications that can continue: publickey,password
>> debug1: Next authentication method: publickey
>> debug1: Offering public key: /home/user/.ssh/id_rsa
>> debug1: Authentications that can continue: publickey,password
>> debug1: Trying private key: /home/user/.ssh/id_dsa
>> debug1: Next authentication method: password
>> user@host's password:
>>=20
>> ***sshd_config file***
>> Port 22
>> Protocol 2
>> HostKey /etc/ssh/ssh_host_rsa_key
>> HostKey /etc/ssh/ssh_host_dsa_key
>> UsePrivilegeSeparation yes
>>=20
>> KeyRegenerationInterval 3600
>> ServerKeyBits 768
>>=20
>> SyslogFacility AUTH
>> LogLevel INFO
>>=20
>> LoginGraceTime 120
>> PermitRootLogin no
>> StrictModes yes
>>=20
>> RSAAuthentication yes
>> PubkeyAuthentication yes
>>=20
>> IgnoreRhosts yes
>> RhostsRSAAuthentication no
>> HostbasedAuthentication no
>>=20
>> PermitEmptyPasswords no
>>=20
>> ChallengeResponseAuthentication no
>>=20
>> X11Forwarding yes
>> X11DisplayOffset 10
>> PrintMotd no
>> PrintLastLog yes
>> TCPKeepAlive yes
>>=20
>> AcceptEnv LANG LC_*
>>=20
>> Subsystem sftp /usr/lib/openssh/sftp-server
>>=20
>> UsePAM yes
>> UseDNS no
>> AllowUsers user
>>=20
>> Thank you for any information about this!
>> Mike
>>=20
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