> ----- Original Message ---- >> From: "aurfalien at gmail.com" <aurfalien at gmail.com> >> To: CentOS mailing list <centos at centos.org> >> Sent: Thu, 21 January, 2010 20:07:27 >> Subject: Re: [CentOS] trouble shooting slow ssh logins >> >>> aurfalien at gmail.com wrote: >>>> Hi all, >>>> >>>> I noticed that my ssh logins to a particular server were taking >>>> up to >>>> 5 seconds to finally login. >>> >>> This is frequently a DNS issue, is forward+reverse DNS functional? >> >> DNS was normal, forward reverse lookups exist and match that host. >> > > Is the server able to to reverse lookups on the IP address of the > incoming client? > > A day or two ago post a suggestion to use UseDNS No in the sshd > config file (from memory), which worked for me. > > HTH. The DNS server also behaved regarding name/ip addy lookups. This server is a Zimbra mail server which during install, checks for proper DNS configs. I usually check proper functioning DNS by hand anyways. The ipv6 line was strange but I read a while back, some tech note about ensuring that is your last line in hosts. - aurf